Merge branch 'master' into testing

47 files changed, 2292 insertions, 1022 deletions

diff --git a/ext/bg/background.html b/ext/bg/background.html
index af87eddb..7fd1c477 100644
--- a/ext/bg/background.html
+++ b/ext/bg/background.html
@@ -26,20 +26,20 @@
         <script src="/bg/js/mecab.js"></script>
         <script src="/bg/js/audio.js"></script>
         <script src="/bg/js/backend-api-forwarder.js"></script>
+        <script src="/bg/js/clipboard-monitor.js"></script>
         <script src="/bg/js/conditions.js"></script>
         <script src="/bg/js/database.js"></script>
         <script src="/bg/js/deinflector.js"></script>
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
+        <script src="/bg/js/japanese.js"></script>
         <script src="/bg/js/json-schema.js"></script>
         <script src="/bg/js/options.js"></script>
         <script src="/bg/js/profile-conditions.js"></script>
         <script src="/bg/js/request.js"></script>
-        <script src="/bg/js/templates.js"></script>
         <script src="/bg/js/translator.js"></script>
         <script src="/bg/js/util.js"></script>
         <script src="/mixed/js/audio.js"></script>
-        <script src="/mixed/js/japanese.js"></script>
 
         <script src="/bg/js/backend.js"></script>
     </body>
diff --git a/ext/bg/css/settings.css b/ext/bg/css/settings.css
index 815a88fa..d686e8f8 100644
--- a/ext/bg/css/settings.css
+++ b/ext/bg/css/settings.css
@@ -222,6 +222,20 @@ html:root[data-operating-system=openbsd] [data-show-for-operating-system~=openbs
     display: initial;
 }
 
+html:root[data-browser=edge] [data-hide-for-browser~=edge],
+html:root[data-browser=chrome] [data-hide-for-browser~=chrome],
+html:root[data-browser=firefox] [data-hide-for-browser~=firefox],
+html:root[data-browser=firefox-mobile] [data-hide-for-browser~=firefox-mobile],
+html:root[data-operating-system=mac] [data-hide-for-operating-system~=mac],
+html:root[data-operating-system=win] [data-hide-for-operating-system~=win],
+html:root[data-operating-system=android] [data-hide-for-operating-system~=android],
+html:root[data-operating-system=cros] [data-hide-for-operating-system~=cros],
+html:root[data-operating-system=linux] [data-hide-for-operating-system~=linux],
+html:root[data-operating-system=openbsd] [data-hide-for-operating-system~=openbsd] {
+    display: none;
+}
+
+
 @media screen and (max-width: 740px) {
     .col-xs-6 {
         float: none;
diff --git a/ext/bg/data/dictionary-index-schema.json b/ext/bg/data/dictionary-index-schema.json
new file mode 100644
index 00000000..9311f14c
--- /dev/null
+++ b/ext/bg/data/dictionary-index-schema.json
@@ -0,0 +1,69 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "object",
+    "description": "Index file containing information about the data contained in the dictionary.",
+    "required": [
+        "title",
+        "revision"
+    ],
+    "properties": {
+        "title": {
+            "type": "string",
+            "description": "Title of the dictionary."
+        },
+        "revision": {
+            "type": "string",
+            "description": "Revision of the dictionary. This value is only used for displaying information."
+        },
+        "sequenced": {
+            "type": "boolean",
+            "default": false,
+            "description": "Whether or not this dictionary can be used as the primary dictionary. Primary dictionaries typically contain term/expression definitions."
+        },
+        "format": {
+            "type": "integer",
+            "description": "Format of data found in the JSON data files.",
+            "enum": [1, 2, 3]
+        },
+        "version": {
+            "type": "integer",
+            "description": "Alias for format.",
+            "enum": [1, 2, 3]
+        },
+        "tagMeta": {
+            "type": "object",
+            "description": "Tag information for terms and kanji. This object is obsolete and individual tag files should be used instead.",
+            "additionalProperties": {
+                "type": "object",
+                "description": "Information about a single tag. The object key is the name of the tag.",
+                "properties": {
+                    "category": {
+                        "type": "string",
+                        "description": "Category for the tag."
+                    },
+                    "order": {
+                        "type": "number",
+                        "description": "Sorting order for the tag."
+                    },
+                    "notes": {
+                        "type": "string",
+                        "description": "Notes for the tag."
+                    },
+                    "score": {
+                        "type": "number",
+                        "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+                    }
+                },
+                "additionalProperties": false
+            }
+        }
+    },
+    "anyOf": [
+        {
+            "required": ["format"]
+        },
+        {
+            "required": ["version"]
+        }
+    ]
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-kanji-bank-v1-schema.json b/ext/bg/data/dictionary-kanji-bank-v1-schema.json
new file mode 100644
index 00000000..6dad5a7a
--- /dev/null
+++ b/ext/bg/data/dictionary-kanji-bank-v1-schema.json
@@ -0,0 +1,33 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing kanji information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single kanji character.",
+        "minItems": 4,
+        "items": [
+            {
+                "type": "string",
+                "description": "Kanji character.",
+                "minLength": 1
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated onyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated kunyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated tags for the kanji character. An empty string is treated as no tags."
+            }
+        ],
+        "additionalItems": {
+            "type": "string",
+            "description": "A meaning for the kanji character."
+        }
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-kanji-bank-v3-schema.json b/ext/bg/data/dictionary-kanji-bank-v3-schema.json
new file mode 100644
index 00000000..a5b82039
--- /dev/null
+++ b/ext/bg/data/dictionary-kanji-bank-v3-schema.json
@@ -0,0 +1,44 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing kanji information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single kanji character.",
+        "minItems": 6,
+        "items": [
+            {
+                "type": "string",
+                "description": "Kanji character.",
+                "minLength": 1
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated onyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated kunyomi readings for the kanji character. An empty string is treated as no readings."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated tags for the kanji character. An empty string is treated as no tags."
+            },
+            {
+                "type": "array",
+                "description": "Array of meanings for the kanji character.",
+                "items": {
+                    "type": "string",
+                    "description": "A meaning for the kanji character."
+                }
+            },
+            {
+                "type": "object",
+                "description": "Various stats for the kanji character.",
+                "additionalProperties": {
+                    "type": "string"
+                }
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-kanji-meta-bank-v3-schema.json b/ext/bg/data/dictionary-kanji-meta-bank-v3-schema.json
new file mode 100644
index 00000000..62479026
--- /dev/null
+++ b/ext/bg/data/dictionary-kanji-meta-bank-v3-schema.json
@@ -0,0 +1,25 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Custom metadata for kanji characters.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Metadata about a single kanji character.",
+        "minItems": 3,
+        "items": [
+            {
+                "type": "string",
+                "minLength": 1
+            },
+            {
+                "type": "string",
+                "enum": ["freq"],
+                "description": "Type of data. \"freq\" corresponds to frequency information."
+            },
+            {
+                "type": ["string", "number"],
+                "description": "Data for the character."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-tag-bank-v3-schema.json b/ext/bg/data/dictionary-tag-bank-v3-schema.json
new file mode 100644
index 00000000..ee5ca64d
--- /dev/null
+++ b/ext/bg/data/dictionary-tag-bank-v3-schema.json
@@ -0,0 +1,32 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing tag information for terms and kanji.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single tag.",
+        "minItems": 5,
+        "items": [
+            {
+                "type": "string",
+                "description": "Tag name."
+            },
+            {
+                "type": "string",
+                "description": "Category for the tag."
+            },
+            {
+                "type": "number",
+                "description": "Sorting order for the tag."
+            },
+            {
+                "type": "string",
+                "description": "Notes for the tag."
+            },
+            {
+                "type": "number",
+                "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-term-bank-v1-schema.json b/ext/bg/data/dictionary-term-bank-v1-schema.json
new file mode 100644
index 00000000..6ffb26e6
--- /dev/null
+++ b/ext/bg/data/dictionary-term-bank-v1-schema.json
@@ -0,0 +1,36 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing term and expression information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single term/expression.",
+        "minItems": 5,
+        "items": [
+            {
+                "type": "string",
+                "description": "Term or expression."
+            },
+            {
+                "type": "string",
+                "description": "Reading of the term/expression, or an empty string if the reading is the same as the term/expression."
+            },
+            {
+                "type": ["string", "null"],
+                "description": "String of space-separated tags for the definition. An empty string is treated as no tags."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated rule identifiers for the definition which is used to validate delinflection. Valid rule identifiers are: v1: ichidan verb; v5: godan verb; vs: suru verb; vk: kuru verb; adj-i: i-adjective. An empty string corresponds to words which aren't inflected, such as nouns."
+            },
+            {
+                "type": "number",
+                "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+            }
+        ],
+        "additionalItems": {
+            "type": "string",
+            "description": "Single definition for the term/expression."
+        }
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-term-bank-v3-schema.json b/ext/bg/data/dictionary-term-bank-v3-schema.json
new file mode 100644
index 00000000..bb982e36
--- /dev/null
+++ b/ext/bg/data/dictionary-term-bank-v3-schema.json
@@ -0,0 +1,48 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Data file containing term and expression information.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Information about a single term/expression.",
+        "minItems": 8,
+        "items": [
+            {
+                "type": "string",
+                "description": "Term or expression."
+            },
+            {
+                "type": "string",
+                "description": "Reading of the term/expression, or an empty string if the reading is the same as the term/expression."
+            },
+            {
+                "type": ["string", "null"],
+                "description": "String of space-separated tags for the definition. An empty string is treated as no tags."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated rule identifiers for the definition which is used to validate delinflection. Valid rule identifiers are: v1: ichidan verb; v5: godan verb; vs: suru verb; vk: kuru verb; adj-i: i-adjective. An empty string corresponds to words which aren't inflected, such as nouns."
+            },
+            {
+                "type": "number",
+                "description": "Score used to determine popularity. Negative values are more rare and positive values are more frequent. This score is also used to sort search results."
+            },
+            {
+                "type": "array",
+                "description": "Array of definitions for the term/expression.",
+                "items": {
+                    "type": "string",
+                    "description": "Single definition for the term/expression."
+                }
+            },
+            {
+                "type": "integer",
+                "description": "Sequence number for the term/expression. Terms/expressions with the same sequence number can be shown together when the \"resultOutputMode\" option is set to \"merge\"."
+            },
+            {
+                "type": "string",
+                "description": "String of space-separated tags for the term/expression. An empty string is treated as no tags."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/dictionary-term-meta-bank-v3-schema.json b/ext/bg/data/dictionary-term-meta-bank-v3-schema.json
new file mode 100644
index 00000000..1cc0557f
--- /dev/null
+++ b/ext/bg/data/dictionary-term-meta-bank-v3-schema.json
@@ -0,0 +1,25 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "type": "array",
+    "description": "Custom metadata for terms/expressions.",
+    "additionalItems": {
+        "type": "array",
+        "description": "Metadata about a single term/expression.",
+        "minItems": 3,
+        "items": [
+            {
+                "type": "string",
+                "description": "Term or expression."
+            },
+            {
+                "type": "string",
+                "enum": ["freq"],
+                "description": "Type of data. \"freq\" corresponds to frequency information."
+            },
+            {
+                "type": ["string", "number"],
+                "description": "Data for the term/expression."
+            }
+        ]
+    }
+}
\ No newline at end of file
diff --git a/ext/bg/data/options-schema.json b/ext/bg/data/options-schema.json
index a20a0619..d6207952 100644
--- a/ext/bg/data/options-schema.json
+++ b/ext/bg/data/options-schema.json
@@ -79,6 +79,7 @@
                                 "type": "object",
                                 "required": [
                                     "enable",
+                                    "enableClipboardPopups",
                                     "resultOutputMode",
                                     "debugInfo",
                                     "maxResults",
@@ -111,6 +112,10 @@
                                         "type": "boolean",
                                         "default": true
                                     },
+                                    "enableClipboardPopups": {
+                                        "type": "boolean",
+                                        "default": false
+                                    },
                                     "resultOutputMode": {
                                         "type": "string",
                                         "enum": ["group", "merge", "split"],
@@ -290,7 +295,8 @@
                                     "popupNestingMaxDepth",
                                     "enablePopupSearch",
                                     "enableOnPopupExpressions",
-                                    "enableOnSearchPage"
+                                    "enableOnSearchPage",
+                                    "enableSearchTags"
                                 ],
                                 "properties": {
                                     "middleMouse": {
@@ -348,6 +354,10 @@
                                     "enableOnSearchPage": {
                                         "type": "boolean",
                                         "default": true
+                                    },
+                                    "enableSearchTags": {
+                                        "type": "boolean",
+                                        "default": false
                                     }
                                 }
                             },
diff --git a/ext/bg/js/anki.js b/ext/bg/js/anki.js
index 10a07061..39c6ad51 100644
--- a/ext/bg/js/anki.js
+++ b/ext/bg/js/anki.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global requestJson*/
 
 /*
  * AnkiConnect
diff --git a/ext/bg/js/api.js b/ext/bg/js/api.js
index 285b8016..0c244ffa 100644
--- a/ext/bg/js/api.js
+++ b/ext/bg/js/api.js
@@ -17,16 +17,16 @@
  */
 
 
-function apiTemplateRender(template, data, dynamic) {
-    return _apiInvoke('templateRender', {data, template, dynamic});
+function apiTemplateRender(template, data) {
+    return _apiInvoke('templateRender', {data, template});
 }
 
 function apiAudioGetUrl(definition, source, optionsContext) {
     return _apiInvoke('audioGetUrl', {definition, source, optionsContext});
 }
 
-function apiGetDisplayTemplatesHtml() {
-    return _apiInvoke('getDisplayTemplatesHtml');
+function apiClipboardGet() {
+    return _apiInvoke('clipboardGet');
 }
 
 function _apiInvoke(action, params={}) {
diff --git a/ext/bg/js/audio.js b/ext/bg/js/audio.js
index 36ac413b..d300570b 100644
--- a/ext/bg/js/audio.js
+++ b/ext/bg/js/audio.js
@@ -16,13 +16,14 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global jpIsStringEntirelyKana, audioGetFromSources*/
 
 const audioUrlBuilders = new Map([
     ['jpod101', async (definition) => {
         let kana = definition.reading;
         let kanji = definition.expression;
 
-        if (!kana && wanakana.isHiragana(kanji)) {
+        if (!kana && jpIsStringEntirelyKana(kanji)) {
             kana = kanji;
             kanji = null;
         }
@@ -51,7 +52,7 @@ const audioUrlBuilders = new Map([
         for (const row of dom.getElementsByClassName('dc-result-row')) {
             try {
                 const url = row.querySelector('audio>source[src]').getAttribute('src');
-                const reading = row.getElementsByClassName('dc-vocab_kana').item(0).innerText;
+                const reading = row.getElementsByClassName('dc-vocab_kana').item(0).textContent;
                 if (url && reading && (!definition.reading || definition.reading === reading)) {
                     return audioUrlNormalize(url, 'https://www.japanesepod101.com', '/learningcenter/reference/');
                 }
@@ -167,10 +168,8 @@ async function audioInject(definition, fields, sources, optionsContext) {
     }
 
     try {
-        let audioSourceDefinition = definition;
-        if (hasOwn(definition, 'expressions')) {
-            audioSourceDefinition = definition.expressions[0];
-        }
+        const expressions = definition.expressions;
+        const audioSourceDefinition = Array.isArray(expressions) ? expressions[0] : definition;
 
         const {url} = await audioGetFromSources(audioSourceDefinition, sources, optionsContext, true);
         if (url !== null) {
diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index eeab68a5..e3bf7bda 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -16,12 +16,21 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global optionsSave, utilIsolate
+conditionsTestValue, profileConditionsDescriptor, profileOptionsGetDefaultFieldTemplates
+handlebarsRenderDynamic
+requestText, requestJson, optionsLoad
+dictConfigured, dictTermsSort, dictEnabledSet, dictNoteFormat
+audioGetUrl, audioInject
+jpConvertReading, jpDistributeFuriganaInflected, jpKatakanaToHiragana
+Translator, AnkiConnect, AnkiNull, Mecab, BackendApiForwarder, JsonSchema, ClipboardMonitor*/
 
 class Backend {
     constructor() {
         this.translator = new Translator();
         this.anki = new AnkiNull();
         this.mecab = new Mecab();
+        this.clipboardMonitor = new ClipboardMonitor();
         this.options = null;
         this.optionsSchema = null;
         this.optionsContext = {
@@ -34,7 +43,11 @@ class Backend {
 
         this.clipboardPasteTarget = document.querySelector('#clipboard-paste-target');
 
+        this.popupWindow = null;
+
         this.apiForwarder = new BackendApiForwarder();
+
+        this.messageToken = yomichan.generateId(16);
     }
 
     async prepare() {
@@ -67,6 +80,8 @@ class Backend {
         this.isPreparedResolve();
         this.isPreparedResolve = null;
         this.isPreparedPromise = null;
+
+        this.clipboardMonitor.onClipboardText = (text) => this._onClipboardText(text);
     }
 
     onOptionsUpdated(source) {
@@ -75,7 +90,7 @@ class Backend {
         const callback = () => this.checkLastError(chrome.runtime.lastError);
         chrome.tabs.query({}, (tabs) => {
             for (const tab of tabs) {
-                chrome.tabs.sendMessage(tab.id, {action: 'optionsUpdate', params: {source}}, callback);
+                chrome.tabs.sendMessage(tab.id, {action: 'optionsUpdated', params: {source}}, callback);
             }
         });
     }
@@ -97,6 +112,10 @@ class Backend {
         }
     }
 
+    _onClipboardText(text) {
+        this._onCommandSearch({mode: 'popup', query: text});
+    }
+
     _onZoomChange({tabId, oldZoomFactor, newZoomFactor}) {
         const callback = () => this.checkLastError(chrome.runtime.lastError);
         chrome.tabs.sendMessage(tabId, {action: 'zoomChanged', params: {oldZoomFactor, newZoomFactor}}, callback);
@@ -121,6 +140,12 @@ class Backend {
         } else {
             this.mecab.stopListener();
         }
+
+        if (options.general.enableClipboardPopups) {
+            this.clipboardMonitor.start();
+        } else {
+            this.clipboardMonitor.stop();
+        }
     }
 
     async getOptionsSchema() {
@@ -249,18 +274,18 @@ class Backend {
                 const node = nodes.pop();
                 for (const key of Object.keys(node.obj)) {
                     const path = node.path.concat(key);
-                    const obj = node.obj[key];
-                    if (obj !== null && typeof obj === 'object') {
-                        nodes.unshift({obj, path});
+                    const obj2 = node.obj[key];
+                    if (obj2 !== null && typeof obj2 === 'object') {
+                        nodes.unshift({obj: obj2, path});
                     } else {
-                        valuePaths.push([obj, path]);
+                        valuePaths.push([obj2, path]);
                     }
                 }
             }
             return valuePaths;
         }
 
-        function modifyOption(path, value, options) {
+        function modifyOption(path, value) {
             let pivot = options;
             for (const key of path.slice(0, -1)) {
                 if (!hasOwn(pivot, key)) {
@@ -273,7 +298,7 @@ class Backend {
         }
 
         for (const [value, path] of getValuePaths(changedOptions)) {
-            modifyOption(path, value, options);
+            modifyOption(path, value);
         }
 
         await this._onApiOptionsSave({source});
@@ -294,7 +319,8 @@ class Backend {
 
     async _onApiTermsFind({text, details, optionsContext}) {
         const options = await this.getOptions(optionsContext);
-        const [definitions, length] = await this.translator.findTerms(text, details, options);
+        const mode = options.general.resultOutputMode;
+        const [definitions, length] = await this.translator.findTerms(mode, text, details, options);
         definitions.splice(options.general.maxResults);
         return {length, definitions};
     }
@@ -304,9 +330,9 @@ class Backend {
         const results = [];
         while (text.length > 0) {
             const term = [];
-            const [definitions, sourceLength] = await this.translator.findTermsInternal(
+            const [definitions, sourceLength] = await this.translator.findTerms(
+                'simple',
                 text.substring(0, options.scanning.length),
-                dictEnabledSet(options),
                 {},
                 options
             );
@@ -314,9 +340,9 @@ class Backend {
                 dictTermsSort(definitions);
                 const {expression, reading} = definitions[0];
                 const source = text.substring(0, sourceLength);
-                for (const {text, furigana} of jpDistributeFuriganaInflected(expression, reading, source)) {
-                    const reading = jpConvertReading(text, furigana, options.parsing.readingMode);
-                    term.push({text, reading});
+                for (const {text: text2, furigana} of jpDistributeFuriganaInflected(expression, reading, source)) {
+                    const reading2 = jpConvertReading(text2, furigana, options.parsing.readingMode);
+                    term.push({text: text2, reading: reading2});
                 }
                 text = text.substring(source.length);
             } else {
@@ -339,17 +365,17 @@ class Backend {
                 for (const {expression, reading, source} of parsedLine) {
                     const term = [];
                     if (expression !== null && reading !== null) {
-                        for (const {text, furigana} of jpDistributeFuriganaInflected(
+                        for (const {text: text2, furigana} of jpDistributeFuriganaInflected(
                             expression,
                             jpKatakanaToHiragana(reading),
                             source
                         )) {
-                            const reading = jpConvertReading(text, furigana, options.parsing.readingMode);
-                            term.push({text, reading});
+                            const reading2 = jpConvertReading(text2, furigana, options.parsing.readingMode);
+                            term.push({text: text2, reading: reading2});
                         }
                     } else {
-                        const reading = jpConvertReading(source, null, options.parsing.readingMode);
-                        term.push({text: source, reading});
+                        const reading2 = jpConvertReading(source, null, options.parsing.readingMode);
+                        term.push({text: source, reading: reading2});
                     }
                     result.push(term);
                 }
@@ -436,12 +462,8 @@ class Backend {
         return this.anki.guiBrowse(`nid:${noteId}`);
     }
 
-    async _onApiTemplateRender({template, data, dynamic}) {
-        return (
-            dynamic ?
-            handlebarsRenderDynamic(template, data) :
-            handlebarsRenderStatic(template, data)
-        );
+    async _onApiTemplateRender({template, data}) {
+        return handlebarsRenderDynamic(template, data);
     }
 
     async _onApiCommandExec({command, params}) {
@@ -480,19 +502,30 @@ class Backend {
         return Promise.resolve({frameId});
     }
 
-    _onApiInjectStylesheet({css}, sender) {
+    _onApiInjectStylesheet({type, value}, sender) {
         if (!sender.tab) {
             return Promise.reject(new Error('Invalid tab'));
         }
 
         const tabId = sender.tab.id;
         const frameId = sender.frameId;
-        const details = {
-            code: css,
-            runAt: 'document_start',
-            cssOrigin: 'user',
-            allFrames: false
-        };
+        const details = (
+            type === 'file' ?
+            {
+                file: value,
+                runAt: 'document_start',
+                cssOrigin: 'author',
+                allFrames: false,
+                matchAboutBlank: true
+            } :
+            {
+                code: value,
+                runAt: 'document_start',
+                cssOrigin: 'user',
+                allFrames: false,
+                matchAboutBlank: true
+            }
+        );
         if (typeof frameId === 'number') {
             details.frameId = frameId;
         }
@@ -521,13 +554,30 @@ class Backend {
     }
 
     async _onApiClipboardGet() {
-        const clipboardPasteTarget = this.clipboardPasteTarget;
-        clipboardPasteTarget.value = '';
-        clipboardPasteTarget.focus();
-        document.execCommand('paste');
-        const result = clipboardPasteTarget.value;
-        clipboardPasteTarget.value = '';
-        return result;
+        /*
+        Notes:
+            document.execCommand('paste') doesn't work on Firefox.
+            This may be a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985
+            Therefore, navigator.clipboard.readText() is used on Firefox.
+
+            navigator.clipboard.readText() can't be used in Chrome for two reasons:
+            * Requires page to be focused, else it rejects with an exception.
+            * When the page is focused, Chrome will request clipboard permission, despite already
+              being an extension with clipboard permissions. It effectively asks for the
+              non-extension permission for clipboard access.
+        */
+        const browser = await Backend._getBrowser();
+        if (browser === 'firefox' || browser === 'firefox-mobile') {
+            return await navigator.clipboard.readText();
+        } else {
+            const clipboardPasteTarget = this.clipboardPasteTarget;
+            clipboardPasteTarget.value = '';
+            clipboardPasteTarget.focus();
+            document.execCommand('paste');
+            const result = clipboardPasteTarget.value;
+            clipboardPasteTarget.value = '';
+            return result;
+        }
     }
 
     async _onApiGetDisplayTemplatesHtml() {
@@ -535,6 +585,11 @@ class Backend {
         return await requestText(url, 'GET');
     }
 
+    async _onApiGetQueryParserTemplatesHtml() {
+        const url = chrome.runtime.getURL('/bg/query-parser-templates.html');
+        return await requestText(url, 'GET');
+    }
+
     _onApiGetZoom(params, sender) {
         if (!sender || !sender.tab) {
             return Promise.reject(new Error('Invalid tab'));
@@ -562,26 +617,75 @@ class Backend {
         });
     }
 
+    async _onApiGetMessageToken() {
+        return this.messageToken;
+    }
+
     // Command handlers
 
     async _onCommandSearch(params) {
-        const url = chrome.runtime.getURL('/bg/search.html');
-        if (!(params && params.newTab)) {
-            try {
-                const tab = await Backend._findTab(1000, (url2) => (
-                    url2 !== null &&
-                    url2.startsWith(url) &&
-                    (url2.length === url.length || url2[url.length] === '?' || url2[url.length] === '#')
-                ));
-                if (tab !== null) {
-                    await Backend._focusTab(tab);
-                    return;
+        const {mode='existingOrNewTab', query} = params || {};
+
+        const options = await this.getOptions(this.optionsContext);
+        const {popupWidth, popupHeight} = options.general;
+
+        const baseUrl = chrome.runtime.getURL('/bg/search.html');
+        const queryParams = {mode};
+        if (query && query.length > 0) { queryParams.query = query; }
+        const queryString = new URLSearchParams(queryParams).toString();
+        const url = `${baseUrl}?${queryString}`;
+
+        const isTabMatch = (url2) => {
+            if (url2 === null || !url2.startsWith(baseUrl)) { return false; }
+            const {baseUrl: baseUrl2, queryParams: queryParams2} = parseUrl(url2);
+            return baseUrl2 === baseUrl && (queryParams2.mode === mode || (!queryParams2.mode && mode === 'existingOrNewTab'));
+        };
+
+        const openInTab = async () => {
+            const tab = await Backend._findTab(1000, isTabMatch);
+            if (tab !== null) {
+                await Backend._focusTab(tab);
+                if (queryParams.query) {
+                    await new Promise((resolve) => chrome.tabs.sendMessage(
+                        tab.id, {action: 'searchQueryUpdate', params: {query: queryParams.query}}, resolve
+                    ));
                 }
-            } catch (e) {
-                // NOP
+                return true;
             }
+        };
+
+        switch (mode) {
+            case 'existingOrNewTab':
+                try {
+                    if (await openInTab()) { return; }
+                } catch (e) {
+                    // NOP
+                }
+                chrome.tabs.create({url});
+                return;
+            case 'newTab':
+                chrome.tabs.create({url});
+                return;
+            case 'popup':
+                try {
+                    // chrome.windows not supported (e.g. on Firefox mobile)
+                    if (!isObject(chrome.windows)) { return; }
+                    if (await openInTab()) { return; }
+                    // if the previous popup is open in an invalid state, close it
+                    if (this.popupWindow !== null) {
+                        const callback = () => this.checkLastError(chrome.runtime.lastError);
+                        chrome.windows.remove(this.popupWindow.id, callback);
+                    }
+                    // open new popup
+                    this.popupWindow = await new Promise((resolve) => chrome.windows.create(
+                        {url, width: popupWidth, height: popupHeight, type: 'popup'},
+                        resolve
+                    ));
+                } catch (e) {
+                    // NOP
+                }
+                return;
         }
-        chrome.tabs.create({url});
     }
 
     _onCommandHelp() {
@@ -697,8 +801,11 @@ class Backend {
         await new Promise((resolve, reject) => {
             chrome.tabs.update(tab.id, {active: true}, () => {
                 const e = chrome.runtime.lastError;
-                if (e) { reject(e); }
-                else { resolve(); }
+                if (e) {
+                    reject(new Error(e.message));
+                } else {
+                    resolve();
+                }
             });
         });
 
@@ -708,19 +815,25 @@ class Backend {
         }
 
         try {
-            const tabWindow = await new Promise((resolve) => {
-                chrome.windows.get(tab.windowId, {}, (tabWindow) => {
+            const tabWindow = await new Promise((resolve, reject) => {
+                chrome.windows.get(tab.windowId, {}, (value) => {
                     const e = chrome.runtime.lastError;
-                    if (e) { reject(e); }
-                    else { resolve(tabWindow); }
+                    if (e) {
+                        reject(new Error(e.message));
+                    } else {
+                        resolve(value);
+                    }
                 });
             });
             if (!tabWindow.focused) {
                 await new Promise((resolve, reject) => {
                     chrome.windows.update(tab.windowId, {focused: true}, () => {
                         const e = chrome.runtime.lastError;
-                        if (e) { reject(e); }
-                        else { resolve(); }
+                        if (e) {
+                            reject(new Error(e.message));
+                        } else {
+                            resolve();
+                        }
                     });
                 });
             }
@@ -777,7 +890,9 @@ Backend._messageHandlers = new Map([
     ['getEnvironmentInfo', (self, ...args) => self._onApiGetEnvironmentInfo(...args)],
     ['clipboardGet', (self, ...args) => self._onApiClipboardGet(...args)],
     ['getDisplayTemplatesHtml', (self, ...args) => self._onApiGetDisplayTemplatesHtml(...args)],
-    ['getZoom', (self, ...args) => self._onApiGetZoom(...args)]
+    ['getQueryParserTemplatesHtml', (self, ...args) => self._onApiGetQueryParserTemplatesHtml(...args)],
+    ['getZoom', (self, ...args) => self._onApiGetZoom(...args)],
+    ['getMessageToken', (self, ...args) => self._onApiGetMessageToken(...args)]
 ]);
 
 Backend._commandHandlers = new Map([
diff --git a/ext/bg/js/clipboard-monitor.js b/ext/bg/js/clipboard-monitor.js
new file mode 100644
index 00000000..c2f41385
--- /dev/null
+++ b/ext/bg/js/clipboard-monitor.js
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*global apiClipboardGet, jpIsStringPartiallyJapanese*/
+
+class ClipboardMonitor {
+    constructor() {
+        this.timerId = null;
+        this.timerToken = null;
+        this.interval = 250;
+        this.previousText = null;
+    }
+
+    onClipboardText(_text) {
+        throw new Error('Override me');
+    }
+
+    start() {
+        this.stop();
+
+        // The token below is used as a unique identifier to ensure that a new clipboard monitor
+        // hasn't been started during the await call. The check below the await apiClipboardGet()
+        // call will exit early if the reference has changed.
+        const token = {};
+        const intervalCallback = async () => {
+            this.timerId = null;
+
+            let text = null;
+            try {
+                text = await apiClipboardGet();
+            } catch (e) {
+                // NOP
+            }
+            if (this.timerToken !== token) { return; }
+
+            if (
+                typeof text === 'string' &&
+                (text = text.trim()).length > 0 &&
+                text !== this.previousText
+            ) {
+                this.previousText = text;
+                if (jpIsStringPartiallyJapanese(text)) {
+                    this.onClipboardText(text);
+                }
+            }
+
+            this.timerId = setTimeout(intervalCallback, this.interval);
+        };
+
+        this.timerToken = token;
+
+        intervalCallback();
+    }
+
+    stop() {
+        this.timerToken = null;
+        if (this.timerId !== null) {
+            clearTimeout(this.timerId);
+            this.timerId = null;
+        }
+    }
+
+    setPreviousText(text) {
+        this.previousText = text;
+    }
+}
diff --git a/ext/bg/js/context.js b/ext/bg/js/context.js
index 834174bf..bec964fb 100644
--- a/ext/bg/js/context.js
+++ b/ext/bg/js/context.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiCommandExec, apiGetEnvironmentInfo, apiOptionsGet*/
 
 function showExtensionInfo() {
     const node = document.getElementById('extension-info');
@@ -30,12 +31,12 @@ function setupButtonEvents(selector, command, url) {
     for (const node of nodes) {
         node.addEventListener('click', (e) => {
             if (e.button !== 0) { return; }
-            apiCommandExec(command, {newTab: e.ctrlKey});
+            apiCommandExec(command, {mode: e.ctrlKey ? 'newTab' : 'existingOrNewTab'});
             e.preventDefault();
         }, false);
         node.addEventListener('auxclick', (e) => {
             if (e.button !== 1) { return; }
-            apiCommandExec(command, {newTab: true});
+            apiCommandExec(command, {mode: 'newTab'});
             e.preventDefault();
         }, false);
 
diff --git a/ext/bg/js/database.js b/ext/bg/js/database.js
index e87cc64b..558f3ceb 100644
--- a/ext/bg/js/database.js
+++ b/ext/bg/js/database.js
@@ -16,20 +16,24 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global dictFieldSplit, requestJson, JsonSchema, JSZip*/
 
 class Database {
     constructor() {
         this.db = null;
+        this._schemas = new Map();
     }
 
+    // Public
+
     async prepare() {
         if (this.db !== null) {
             throw new Error('Database already initialized');
         }
 
         try {
-            this.db = await Database.open('dict', 5, (db, transaction, oldVersion) => {
-                Database.upgrade(db, transaction, oldVersion, [
+            this.db = await Database._open('dict', 5, (db, transaction, oldVersion) => {
+                Database._upgrade(db, transaction, oldVersion, [
                     {
                         version: 2,
                         stores: {
@@ -95,18 +99,24 @@ class Database {
         }
     }
 
+    async close() {
+        this._validate();
+        this.db.close();
+        this.db = null;
+    }
+
     async purge() {
-        this.validate();
+        this._validate();
 
         this.db.close();
-        await Database.deleteDatabase(this.db.name);
+        await Database._deleteDatabase(this.db.name);
         this.db = null;
 
         await this.prepare();
     }
 
     async deleteDictionary(dictionaryName, onProgress, progressSettings) {
-        this.validate();
+        this._validate();
 
         const targets = [
             ['dictionaries', 'title'],
@@ -133,22 +143,22 @@ class Database {
             const dbObjectStore = dbTransaction.objectStore(objectStoreName);
             const dbIndex = dbObjectStore.index(index);
             const only = IDBKeyRange.only(dictionaryName);
-            promises.push(Database.deleteValues(dbObjectStore, dbIndex, only, onProgress, progressData, progressRate));
+            promises.push(Database._deleteValues(dbObjectStore, dbIndex, only, onProgress, progressData, progressRate));
         }
 
         await Promise.all(promises);
     }
 
-    async findTermsBulk(termList, titles, wildcard) {
-        this.validate();
+    async findTermsBulk(termList, dictionaries, wildcard) {
+        this._validate();
 
         const promises = [];
-        const visited = {};
+        const visited = new Set();
         const results = [];
         const processRow = (row, index) => {
-            if (titles.includes(row.dictionary) && !hasOwn(visited, row.id)) {
-                visited[row.id] = true;
-                results.push(Database.createTerm(row, index));
+            if (dictionaries.has(row.dictionary) && !visited.has(row.id)) {
+                visited.add(row.id);
+                results.push(Database._createTerm(row, index));
             }
         };
 
@@ -164,8 +174,8 @@ class Database {
             const term = prefixWildcard ? stringReverse(termList[i]) : termList[i];
             const query = useWildcard ? IDBKeyRange.bound(term, `${term}\uffff`, false, false) : IDBKeyRange.only(term);
             promises.push(
-                Database.getAll(dbIndex1, query, i, processRow),
-                Database.getAll(dbIndex2, query, i, processRow)
+                Database._getAll(dbIndex1, query, i, processRow),
+                Database._getAll(dbIndex2, query, i, processRow)
             );
         }
 
@@ -174,14 +184,14 @@ class Database {
         return results;
     }
 
-    async findTermsExactBulk(termList, readingList, titles) {
-        this.validate();
+    async findTermsExactBulk(termList, readingList, dictionaries) {
+        this._validate();
 
         const promises = [];
         const results = [];
         const processRow = (row, index) => {
-            if (row.reading === readingList[index] && titles.includes(row.dictionary)) {
-                results.push(Database.createTerm(row, index));
+            if (row.reading === readingList[index] && dictionaries.has(row.dictionary)) {
+                results.push(Database._createTerm(row, index));
             }
         };
 
@@ -191,7 +201,7 @@ class Database {
 
         for (let i = 0; i < termList.length; ++i) {
             const only = IDBKeyRange.only(termList[i]);
-            promises.push(Database.getAll(dbIndex, only, i, processRow));
+            promises.push(Database._getAll(dbIndex, only, i, processRow));
         }
 
         await Promise.all(promises);
@@ -200,13 +210,13 @@ class Database {
     }
 
     async findTermsBySequenceBulk(sequenceList, mainDictionary) {
-        this.validate();
+        this._validate();
 
         const promises = [];
         const results = [];
         const processRow = (row, index) => {
             if (row.dictionary === mainDictionary) {
-                results.push(Database.createTerm(row, index));
+                results.push(Database._createTerm(row, index));
             }
         };
 
@@ -216,7 +226,7 @@ class Database {
 
         for (let i = 0; i < sequenceList.length; ++i) {
             const only = IDBKeyRange.only(sequenceList[i]);
-            promises.push(Database.getAll(dbIndex, only, i, processRow));
+            promises.push(Database._getAll(dbIndex, only, i, processRow));
         }
 
         await Promise.all(promises);
@@ -224,52 +234,27 @@ class Database {
         return results;
     }
 
-    async findTermMetaBulk(termList, titles) {
-        return this.findGenericBulk('termMeta', 'expression', termList, titles, Database.createTermMeta);
+    async findTermMetaBulk(termList, dictionaries) {
+        return this._findGenericBulk('termMeta', 'expression', termList, dictionaries, Database._createTermMeta);
     }
 
-    async findKanjiBulk(kanjiList, titles) {
-        return this.findGenericBulk('kanji', 'character', kanjiList, titles, Database.createKanji);
+    async findKanjiBulk(kanjiList, dictionaries) {
+        return this._findGenericBulk('kanji', 'character', kanjiList, dictionaries, Database._createKanji);
     }
 
-    async findKanjiMetaBulk(kanjiList, titles) {
-        return this.findGenericBulk('kanjiMeta', 'character', kanjiList, titles, Database.createKanjiMeta);
-    }
-
-    async findGenericBulk(tableName, indexName, indexValueList, titles, createResult) {
-        this.validate();
-
-        const promises = [];
-        const results = [];
-        const processRow = (row, index) => {
-            if (titles.includes(row.dictionary)) {
-                results.push(createResult(row, index));
-            }
-        };
-
-        const dbTransaction = this.db.transaction([tableName], 'readonly');
-        const dbTerms = dbTransaction.objectStore(tableName);
-        const dbIndex = dbTerms.index(indexName);
-
-        for (let i = 0; i < indexValueList.length; ++i) {
-            const only = IDBKeyRange.only(indexValueList[i]);
-            promises.push(Database.getAll(dbIndex, only, i, processRow));
-        }
-
-        await Promise.all(promises);
-
-        return results;
+    async findKanjiMetaBulk(kanjiList, dictionaries) {
+        return this._findGenericBulk('kanjiMeta', 'character', kanjiList, dictionaries, Database._createKanjiMeta);
     }
 
     async findTagForTitle(name, title) {
-        this.validate();
+        this._validate();
 
         let result = null;
         const dbTransaction = this.db.transaction(['tagMeta'], 'readonly');
         const dbTerms = dbTransaction.objectStore('tagMeta');
         const dbIndex = dbTerms.index('name');
         const only = IDBKeyRange.only(name);
-        await Database.getAll(dbIndex, only, null, (row) => {
+        await Database._getAll(dbIndex, only, null, (row) => {
             if (title === row.dictionary) {
                 result = row;
             }
@@ -279,19 +264,19 @@ class Database {
     }
 
     async getDictionaryInfo() {
-        this.validate();
+        this._validate();
 
         const results = [];
         const dbTransaction = this.db.transaction(['dictionaries'], 'readonly');
         const dbDictionaries = dbTransaction.objectStore('dictionaries');
 
-        await Database.getAll(dbDictionaries, null, null, (info) => results.push(info));
+        await Database._getAll(dbDictionaries, null, null, (info) => results.push(info));
 
         return results;
     }
 
     async getDictionaryCounts(dictionaryNames, getTotal) {
-        this.validate();
+        this._validate();
 
         const objectStoreNames = [
             'kanji',
@@ -312,7 +297,7 @@ class Database {
 
         // Query is required for Edge, otherwise index.count throws an exception.
         const query1 = IDBKeyRange.lowerBound('', false);
-        const totalPromise = getTotal ? Database.getCounts(targets, query1) : null;
+        const totalPromise = getTotal ? Database._getCounts(targets, query1) : null;
 
         const counts = [];
         const countPromises = [];
@@ -320,7 +305,7 @@ class Database {
             counts.push(null);
             const index = i;
             const query2 = IDBKeyRange.only(dictionaryNames[i]);
-            const countPromise = Database.getCounts(targets, query2).then((v) => counts[index] = v);
+            const countPromise = Database._getCounts(targets, query2).then((v) => counts[index] = v);
             countPromises.push(countPromise);
         }
         await Promise.all(countPromises);
@@ -332,278 +317,287 @@ class Database {
         return result;
     }
 
-    async importDictionary(archive, progressCallback, details) {
-        this.validate();
+    async importDictionary(archiveSource, onProgress, details) {
+        this._validate();
+        const db = this.db;
+        const hasOnProgress = (typeof onProgress === 'function');
 
-        const errors = [];
-        const prefixWildcardsSupported = details.prefixWildcardsSupported;
+        // Read archive
+        const archive = await JSZip.loadAsync(archiveSource);
 
-        const maxTransactionLength = 1000;
-        const bulkAdd = async (objectStoreName, items, total, current) => {
-            const db = this.db;
-            for (let i = 0; i < items.length; i += maxTransactionLength) {
-                if (progressCallback) {
-                    progressCallback(total, current + i / items.length);
-                }
+        // Read and validate index
+        const indexFileName = 'index.json';
+        const indexFile = archive.files[indexFileName];
+        if (!indexFile) {
+            throw new Error('No dictionary index found in archive');
+        }
 
-                try {
-                    const count = Math.min(maxTransactionLength, items.length - i);
-                    const transaction = db.transaction([objectStoreName], 'readwrite');
-                    const objectStore = transaction.objectStore(objectStoreName);
-                    await Database.bulkAdd(objectStore, items, i, count);
-                } catch (e) {
-                    errors.push(e);
-                }
-            }
-        };
+        const index = JSON.parse(await indexFile.async('string'));
 
-        const indexDataLoaded = async (summary) => {
-            if (summary.version > 3) {
-                throw new Error('Unsupported dictionary version');
-            }
+        const indexSchema = await this._getSchema('/bg/data/dictionary-index-schema.json');
+        Database._validateJsonSchema(index, indexSchema, indexFileName);
 
-            const db = this.db;
-            const dbCountTransaction = db.transaction(['dictionaries'], 'readonly');
-            const dbIndex = dbCountTransaction.objectStore('dictionaries').index('title');
-            const only = IDBKeyRange.only(summary.title);
-            const count = await Database.getCount(dbIndex, only);
+        const dictionaryTitle = index.title;
+        const version = index.format || index.version;
 
-            if (count > 0) {
-                throw new Error('Dictionary is already imported');
-            }
+        if (!dictionaryTitle || !index.revision) {
+            throw new Error('Unrecognized dictionary format');
+        }
 
-            const transaction = db.transaction(['dictionaries'], 'readwrite');
-            const objectStore = transaction.objectStore('dictionaries');
-            await Database.bulkAdd(objectStore, [summary], 0, 1);
-        };
+        // Verify database is not already imported
+        if (await this._dictionaryExists(dictionaryTitle)) {
+            throw new Error('Dictionary is already imported');
+        }
 
-        const termDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            if (summary.version === 1) {
-                for (const [expression, reading, definitionTags, rules, score, ...glossary] of entries) {
-                    rows.push({
-                        expression,
-                        reading,
-                        definitionTags,
-                        rules,
-                        score,
-                        glossary,
-                        dictionary: summary.title
-                    });
-                }
+        // Data format converters
+        const convertTermBankEntry = (entry) => {
+            if (version === 1) {
+                const [expression, reading, definitionTags, rules, score, ...glossary] = entry;
+                return {expression, reading, definitionTags, rules, score, glossary};
             } else {
-                for (const [expression, reading, definitionTags, rules, score, glossary, sequence, termTags] of entries) {
-                    rows.push({
-                        expression,
-                        reading,
-                        definitionTags,
-                        rules,
-                        score,
-                        glossary,
-                        sequence,
-                        termTags,
-                        dictionary: summary.title
-                    });
-                }
-            }
-
-            if (prefixWildcardsSupported) {
-                for (const row of rows) {
-                    row.expressionReverse = stringReverse(row.expression);
-                    row.readingReverse = stringReverse(row.reading);
-                }
+                const [expression, reading, definitionTags, rules, score, glossary, sequence, termTags] = entry;
+                return {expression, reading, definitionTags, rules, score, glossary, sequence, termTags};
             }
+        };
 
-            await bulkAdd('terms', rows, total, current);
+        const convertTermMetaBankEntry = (entry) => {
+            const [expression, mode, data] = entry;
+            return {expression, mode, data};
         };
 
-        const termMetaDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            for (const [expression, mode, data] of entries) {
-                rows.push({
-                    expression,
-                    mode,
-                    data,
-                    dictionary: summary.title
-                });
+        const convertKanjiBankEntry = (entry) => {
+            if (version === 1) {
+                const [character, onyomi, kunyomi, tags, ...meanings] = entry;
+                return {character, onyomi, kunyomi, tags, meanings};
+            } else {
+                const [character, onyomi, kunyomi, tags, meanings, stats] = entry;
+                return {character, onyomi, kunyomi, tags, meanings, stats};
             }
+        };
 
-            await bulkAdd('termMeta', rows, total, current);
+        const convertKanjiMetaBankEntry = (entry) => {
+            const [character, mode, data] = entry;
+            return {character, mode, data};
         };
 
-        const kanjiDataLoaded = async (summary, entries, total, current)  => {
-            const rows = [];
-            if (summary.version === 1) {
-                for (const [character, onyomi, kunyomi, tags, ...meanings] of entries) {
-                    rows.push({
-                        character,
-                        onyomi,
-                        kunyomi,
-                        tags,
-                        meanings,
-                        dictionary: summary.title
-                    });
-                }
-            } else {
-                for (const [character, onyomi, kunyomi, tags, meanings, stats] of entries) {
-                    rows.push({
-                        character,
-                        onyomi,
-                        kunyomi,
-                        tags,
-                        meanings,
-                        stats,
-                        dictionary: summary.title
-                    });
+        const convertTagBankEntry = (entry) => {
+            const [name, category, order, notes, score] = entry;
+            return {name, category, order, notes, score};
+        };
+
+        // Archive file reading
+        const readFileSequence = async (fileNameFormat, convertEntry, schema) => {
+            const results = [];
+            for (let i = 1; true; ++i) {
+                const fileName = fileNameFormat.replace(/\?/, `${i}`);
+                const file = archive.files[fileName];
+                if (!file) { break; }
+
+                const entries = JSON.parse(await file.async('string'));
+                Database._validateJsonSchema(entries, schema, fileName);
+
+                for (let entry of entries) {
+                    entry = convertEntry(entry);
+                    entry.dictionary = dictionaryTitle;
+                    results.push(entry);
                 }
             }
-
-            await bulkAdd('kanji', rows, total, current);
+            return results;
         };
 
-        const kanjiMetaDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            for (const [character, mode, data] of entries) {
-                rows.push({
-                    character,
-                    mode,
-                    data,
-                    dictionary: summary.title
-                });
+        // Load schemas
+        const dataBankSchemaPaths = this.constructor._getDataBankSchemaPaths(version);
+        const dataBankSchemas = await Promise.all(dataBankSchemaPaths.map((path) => this._getSchema(path)));
+
+        // Load data
+        const termList      = await readFileSequence('term_bank_?.json',       convertTermBankEntry,      dataBankSchemas[0]);
+        const termMetaList  = await readFileSequence('term_meta_bank_?.json',  convertTermMetaBankEntry,  dataBankSchemas[1]);
+        const kanjiList     = await readFileSequence('kanji_bank_?.json',      convertKanjiBankEntry,     dataBankSchemas[2]);
+        const kanjiMetaList = await readFileSequence('kanji_meta_bank_?.json', convertKanjiMetaBankEntry, dataBankSchemas[3]);
+        const tagList       = await readFileSequence('tag_bank_?.json',        convertTagBankEntry,       dataBankSchemas[4]);
+
+        // Old tags
+        const indexTagMeta = index.tagMeta;
+        if (typeof indexTagMeta === 'object' && indexTagMeta !== null) {
+            for (const name of Object.keys(indexTagMeta)) {
+                const {category, order, notes, score} = indexTagMeta[name];
+                tagList.push({name, category, order, notes, score});
             }
+        }
 
-            await bulkAdd('kanjiMeta', rows, total, current);
-        };
-
-        const tagDataLoaded = async (summary, entries, total, current) => {
-            const rows = [];
-            for (const [name, category, order, notes, score] of entries) {
-                const row = dictTagSanitize({
-                    name,
-                    category,
-                    order,
-                    notes,
-                    score,
-                    dictionary: summary.title
-                });
-
-                rows.push(row);
+        // Prefix wildcard support
+        const prefixWildcardsSupported = !!details.prefixWildcardsSupported;
+        if (prefixWildcardsSupported) {
+            for (const entry of termList) {
+                entry.expressionReverse = stringReverse(entry.expression);
+                entry.readingReverse = stringReverse(entry.reading);
             }
+        }
 
-            await bulkAdd('tagMeta', rows, total, current);
+        // Add dictionary
+        const summary = {
+            title: dictionaryTitle,
+            revision: index.revision,
+            sequenced: index.sequenced,
+            version,
+            prefixWildcardsSupported
         };
 
-        const result = await Database.importDictionaryZip(
-            archive,
-            indexDataLoaded,
-            termDataLoaded,
-            termMetaDataLoaded,
-            kanjiDataLoaded,
-            kanjiMetaDataLoaded,
-            tagDataLoaded,
-            details
+        {
+            const transaction = db.transaction(['dictionaries'], 'readwrite');
+            const objectStore = transaction.objectStore('dictionaries');
+            await Database._bulkAdd(objectStore, [summary], 0, 1);
+        }
+
+        // Add data
+        const errors = [];
+        const total = (
+            termList.length +
+            termMetaList.length +
+            kanjiList.length +
+            kanjiMetaList.length +
+            tagList.length
         );
+        let loadedCount = 0;
+        const maxTransactionLength = 1000;
+
+        const bulkAdd = async (objectStoreName, entries) => {
+            const ii = entries.length;
+            for (let i = 0; i < ii; i += maxTransactionLength) {
+                const count = Math.min(maxTransactionLength, ii - i);
+
+                try {
+                    const transaction = db.transaction([objectStoreName], 'readwrite');
+                    const objectStore = transaction.objectStore(objectStoreName);
+                    await Database._bulkAdd(objectStore, entries, i, count);
+                } catch (e) {
+                    errors.push(e);
+                }
 
-        return {result, errors};
+                loadedCount += count;
+                if (hasOnProgress) {
+                    onProgress(total, loadedCount);
+                }
+            }
+        };
+
+        await bulkAdd('terms', termList);
+        await bulkAdd('termMeta', termMetaList);
+        await bulkAdd('kanji', kanjiList);
+        await bulkAdd('kanjiMeta', kanjiMetaList);
+        await bulkAdd('tagMeta', tagList);
+
+        return {result: summary, errors};
     }
 
-    validate() {
+    // Private
+
+    _validate() {
         if (this.db === null) {
             throw new Error('Database not initialized');
         }
     }
 
-    static async importDictionaryZip(
-        archive,
-        indexDataLoaded,
-        termDataLoaded,
-        termMetaDataLoaded,
-        kanjiDataLoaded,
-        kanjiMetaDataLoaded,
-        tagDataLoaded,
-        details
-    ) {
-        const zip = await JSZip.loadAsync(archive);
-
-        const indexFile = zip.files['index.json'];
-        if (!indexFile) {
-            throw new Error('No dictionary index found in archive');
+    async _getSchema(fileName) {
+        let schemaPromise = this._schemas.get(fileName);
+        if (typeof schemaPromise !== 'undefined') {
+            return schemaPromise;
         }
 
-        const index = JSON.parse(await indexFile.async('string'));
-        if (!index.title || !index.revision) {
-            throw new Error('Unrecognized dictionary format');
+        schemaPromise = requestJson(chrome.runtime.getURL(fileName), 'GET');
+        this._schemas.set(fileName, schemaPromise);
+        return schemaPromise;
+    }
+
+    static _validateJsonSchema(value, schema, fileName) {
+        try {
+            JsonSchema.validate(value, schema);
+        } catch (e) {
+            throw Database._formatSchemaError(e, fileName);
         }
+    }
 
-        const summary = {
-            title: index.title,
-            revision: index.revision,
-            sequenced: index.sequenced,
-            version: index.format || index.version,
-            prefixWildcardsSupported: !!details.prefixWildcardsSupported
-        };
+    static _formatSchemaError(e, fileName) {
+        const valuePathString = Database._getSchemaErrorPathString(e.info.valuePath, 'dictionary');
+        const schemaPathString = Database._getSchemaErrorPathString(e.info.schemaPath, 'schema');
 
-        await indexDataLoaded(summary);
+        const e2 = new Error(`Dictionary has invalid data in '${fileName}' for value '${valuePathString}', validated against '${schemaPathString}': ${e.message}`);
+        e2.data = e;
 
-        const buildTermBankName      = (index) => `term_bank_${index + 1}.json`;
-        const buildTermMetaBankName  = (index) => `term_meta_bank_${index + 1}.json`;
-        const buildKanjiBankName     = (index) => `kanji_bank_${index + 1}.json`;
-        const buildKanjiMetaBankName = (index) => `kanji_meta_bank_${index + 1}.json`;
-        const buildTagBankName       = (index) => `tag_bank_${index + 1}.json`;
+        return e2;
+    }
 
-        const countBanks = (namer) => {
-            let count = 0;
-            while (zip.files[namer(count)]) {
-                ++count;
+    static _getSchemaErrorPathString(infoList, base='') {
+        let result = base;
+        for (const [part] of infoList) {
+            switch (typeof part) {
+                case 'string':
+                    if (result.length > 0) {
+                        result += '.';
+                    }
+                    result += part;
+                    break;
+                case 'number':
+                    result += `[${part}]`;
+                    break;
             }
+        }
+        return result;
+    }
 
-            return count;
-        };
+    static _getDataBankSchemaPaths(version) {
+        const termBank = (
+            version === 1 ?
+            '/bg/data/dictionary-term-bank-v1-schema.json' :
+            '/bg/data/dictionary-term-bank-v3-schema.json'
+        );
+        const termMetaBank = '/bg/data/dictionary-term-meta-bank-v3-schema.json';
+        const kanjiBank = (
+            version === 1 ?
+            '/bg/data/dictionary-kanji-bank-v1-schema.json' :
+            '/bg/data/dictionary-kanji-bank-v3-schema.json'
+        );
+        const kanjiMetaBank = '/bg/data/dictionary-kanji-meta-bank-v3-schema.json';
+        const tagBank = '/bg/data/dictionary-tag-bank-v3-schema.json';
 
-        const termBankCount      = countBanks(buildTermBankName);
-        const termMetaBankCount  = countBanks(buildTermMetaBankName);
-        const kanjiBankCount     = countBanks(buildKanjiBankName);
-        const kanjiMetaBankCount = countBanks(buildKanjiMetaBankName);
-        const tagBankCount       = countBanks(buildTagBankName);
-
-        let bankLoadedCount = 0;
-        let bankTotalCount =
-            termBankCount +
-            termMetaBankCount +
-            kanjiBankCount +
-            kanjiMetaBankCount +
-            tagBankCount;
-
-        if (tagDataLoaded && index.tagMeta) {
-            const bank = [];
-            for (const name in index.tagMeta) {
-                const tag = index.tagMeta[name];
-                bank.push([name, tag.category, tag.order, tag.notes, tag.score]);
-            }
+        return [termBank, termMetaBank, kanjiBank, kanjiMetaBank, tagBank];
+    }
 
-            tagDataLoaded(summary, bank, ++bankTotalCount, bankLoadedCount++);
-        }
+    async _dictionaryExists(title) {
+        const db = this.db;
+        const dbCountTransaction = db.transaction(['dictionaries'], 'readonly');
+        const dbIndex = dbCountTransaction.objectStore('dictionaries').index('title');
+        const only = IDBKeyRange.only(title);
+        const count = await Database._getCount(dbIndex, only);
+        return count > 0;
+    }
 
-        const loadBank = async (summary, namer, count, callback) => {
-            if (callback) {
-                for (let i = 0; i < count; ++i) {
-                    const bankFile = zip.files[namer(i)];
-                    const bank = JSON.parse(await bankFile.async('string'));
-                    await callback(summary, bank, bankTotalCount, bankLoadedCount++);
-                }
+    async _findGenericBulk(tableName, indexName, indexValueList, dictionaries, createResult) {
+        this._validate();
+
+        const promises = [];
+        const results = [];
+        const processRow = (row, index) => {
+            if (dictionaries.has(row.dictionary)) {
+                results.push(createResult(row, index));
             }
         };
 
-        await loadBank(summary, buildTermBankName, termBankCount, termDataLoaded);
-        await loadBank(summary, buildTermMetaBankName, termMetaBankCount, termMetaDataLoaded);
-        await loadBank(summary, buildKanjiBankName, kanjiBankCount, kanjiDataLoaded);
-        await loadBank(summary, buildKanjiMetaBankName, kanjiMetaBankCount, kanjiMetaDataLoaded);
-        await loadBank(summary, buildTagBankName, tagBankCount, tagDataLoaded);
+        const dbTransaction = this.db.transaction([tableName], 'readonly');
+        const dbTerms = dbTransaction.objectStore(tableName);
+        const dbIndex = dbTerms.index(indexName);
+
+        for (let i = 0; i < indexValueList.length; ++i) {
+            const only = IDBKeyRange.only(indexValueList[i]);
+            promises.push(Database._getAll(dbIndex, only, i, processRow));
+        }
+
+        await Promise.all(promises);
 
-        return summary;
+        return results;
     }
 
-    static createTerm(row, index) {
+    static _createTerm(row, index) {
         return {
             index,
             expression: row.expression,
@@ -619,7 +613,7 @@ class Database {
         };
     }
 
-    static createKanji(row, index) {
+    static _createKanji(row, index) {
         return {
             index,
             character: row.character,
@@ -632,20 +626,20 @@ class Database {
         };
     }
 
-    static createTermMeta({expression, mode, data, dictionary}, index) {
+    static _createTermMeta({expression, mode, data, dictionary}, index) {
         return {expression, mode, data, dictionary, index};
     }
 
-    static createKanjiMeta({character, mode, data, dictionary}, index) {
+    static _createKanjiMeta({character, mode, data, dictionary}, index) {
         return {character, mode, data, dictionary, index};
     }
 
-    static getAll(dbIndex, query, context, processRow) {
-        const fn = typeof dbIndex.getAll === 'function' ? Database.getAllFast : Database.getAllUsingCursor;
+    static _getAll(dbIndex, query, context, processRow) {
+        const fn = typeof dbIndex.getAll === 'function' ? Database._getAllFast : Database._getAllUsingCursor;
         return fn(dbIndex, query, context, processRow);
     }
 
-    static getAllFast(dbIndex, query, context, processRow) {
+    static _getAllFast(dbIndex, query, context, processRow) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.getAll(query);
             request.onerror = (e) => reject(e);
@@ -658,7 +652,7 @@ class Database {
         });
     }
 
-    static getAllUsingCursor(dbIndex, query, context, processRow) {
+    static _getAllUsingCursor(dbIndex, query, context, processRow) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.openCursor(query, 'next');
             request.onerror = (e) => reject(e);
@@ -674,18 +668,18 @@ class Database {
         });
     }
 
-    static getCounts(targets, query) {
+    static _getCounts(targets, query) {
         const countPromises = [];
         const counts = {};
         for (const [objectStoreName, index] of targets) {
             const n = objectStoreName;
-            const countPromise = Database.getCount(index, query).then((count) => counts[n] = count);
+            const countPromise = Database._getCount(index, query).then((count) => counts[n] = count);
             countPromises.push(countPromise);
         }
         return Promise.all(countPromises).then(() => counts);
     }
 
-    static getCount(dbIndex, query) {
+    static _getCount(dbIndex, query) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.count(query);
             request.onerror = (e) => reject(e);
@@ -693,12 +687,12 @@ class Database {
         });
     }
 
-    static getAllKeys(dbIndex, query) {
-        const fn = typeof dbIndex.getAllKeys === 'function' ? Database.getAllKeysFast : Database.getAllKeysUsingCursor;
+    static _getAllKeys(dbIndex, query) {
+        const fn = typeof dbIndex.getAllKeys === 'function' ? Database._getAllKeysFast : Database._getAllKeysUsingCursor;
         return fn(dbIndex, query);
     }
 
-    static getAllKeysFast(dbIndex, query) {
+    static _getAllKeysFast(dbIndex, query) {
         return new Promise((resolve, reject) => {
             const request = dbIndex.getAllKeys(query);
             request.onerror = (e) => reject(e);
@@ -706,7 +700,7 @@ class Database {
         });
     }
 
-    static getAllKeysUsingCursor(dbIndex, query) {
+    static _getAllKeysUsingCursor(dbIndex, query) {
         return new Promise((resolve, reject) => {
             const primaryKeys = [];
             const request = dbIndex.openKeyCursor(query, 'next');
@@ -723,9 +717,9 @@ class Database {
         });
     }
 
-    static async deleteValues(dbObjectStore, dbIndex, query, onProgress, progressData, progressRate) {
+    static async _deleteValues(dbObjectStore, dbIndex, query, onProgress, progressData, progressRate) {
         const hasProgress = (typeof onProgress === 'function');
-        const count = await Database.getCount(dbIndex, query);
+        const count = await Database._getCount(dbIndex, query);
         ++progressData.storesProcesed;
         progressData.count += count;
         if (hasProgress) {
@@ -744,16 +738,16 @@ class Database {
         );
 
         const promises = [];
-        const primaryKeys = await Database.getAllKeys(dbIndex, query);
+        const primaryKeys = await Database._getAllKeys(dbIndex, query);
         for (const key of primaryKeys) {
-            const promise = Database.deleteValue(dbObjectStore, key).then(onValueDeleted);
+            const promise = Database._deleteValue(dbObjectStore, key).then(onValueDeleted);
             promises.push(promise);
         }
 
         await Promise.all(promises);
     }
 
-    static deleteValue(dbObjectStore, key) {
+    static _deleteValue(dbObjectStore, key) {
         return new Promise((resolve, reject) => {
             const request = dbObjectStore.delete(key);
             request.onerror = (e) => reject(e);
@@ -761,7 +755,7 @@ class Database {
         });
     }
 
-    static bulkAdd(objectStore, items, start, count) {
+    static _bulkAdd(objectStore, items, start, count) {
         return new Promise((resolve, reject) => {
             if (start + count > items.length) {
                 count = items.length - start;
@@ -789,7 +783,7 @@ class Database {
         });
     }
 
-    static open(name, version, onUpgradeNeeded) {
+    static _open(name, version, onUpgradeNeeded) {
         return new Promise((resolve, reject) => {
             const request = window.indexedDB.open(name, version * 10);
 
@@ -807,7 +801,7 @@ class Database {
         });
     }
 
-    static upgrade(db, transaction, oldVersion, upgrades) {
+    static _upgrade(db, transaction, oldVersion, upgrades) {
         for (const {version, stores} of upgrades) {
             if (oldVersion >= version) { continue; }
 
@@ -815,15 +809,15 @@ class Database {
             for (const objectStoreName of objectStoreNames) {
                 const {primaryKey, indices} = stores[objectStoreName];
 
-                const objectStoreNames = transaction.objectStoreNames || db.objectStoreNames;
+                const objectStoreNames2 = transaction.objectStoreNames || db.objectStoreNames;
                 const objectStore = (
-                    Database.listContains(objectStoreNames, objectStoreName) ?
+                    Database._listContains(objectStoreNames2, objectStoreName) ?
                     transaction.objectStore(objectStoreName) :
                     db.createObjectStore(objectStoreName, primaryKey)
                 );
 
                 for (const indexName of indices) {
-                    if (Database.listContains(objectStore.indexNames, indexName)) { continue; }
+                    if (Database._listContains(objectStore.indexNames, indexName)) { continue; }
 
                     objectStore.createIndex(indexName, indexName, {});
                 }
@@ -831,7 +825,7 @@ class Database {
         }
     }
 
-    static deleteDatabase(dbName) {
+    static _deleteDatabase(dbName) {
         return new Promise((resolve, reject) => {
             const request = indexedDB.deleteDatabase(dbName);
             request.onerror = (e) => reject(e);
@@ -839,7 +833,7 @@ class Database {
         });
     }
 
-    static listContains(list, value) {
+    static _listContains(list, value) {
         for (let i = 0, ii = list.length; i < ii; ++i) {
             if (list[i] === value) { return true; }
         }
diff --git a/ext/bg/js/deinflector.js b/ext/bg/js/deinflector.js
index 33b2a8b3..e2ced965 100644
--- a/ext/bg/js/deinflector.js
+++ b/ext/bg/js/deinflector.js
@@ -76,17 +76,19 @@ class Deinflector {
         const ruleTypes = Deinflector.ruleTypes;
         let value = 0;
         for (const rule of rules) {
-            value |= ruleTypes[rule];
+            const ruleBits = ruleTypes.get(rule);
+            if (typeof ruleBits === 'undefined') { continue; }
+            value |= ruleBits;
         }
         return value;
     }
 }
 
-Deinflector.ruleTypes = {
-    'v1':    0b0000001, // Verb ichidan
-    'v5':    0b0000010, // Verb godan
-    'vs':    0b0000100, // Verb suru
-    'vk':    0b0001000, // Verb kuru
-    'adj-i': 0b0010000, // Adjective i
-    'iru':   0b0100000  // Intermediate -iru endings for progressive or perfect tense
-};
+Deinflector.ruleTypes = new Map([
+    ['v1',    0b0000001], // Verb ichidan
+    ['v5',    0b0000010], // Verb godan
+    ['vs',    0b0000100], // Verb suru
+    ['vk',    0b0001000], // Verb kuru
+    ['adj-i', 0b0010000], // Adjective i
+    ['iru',   0b0100000] // Intermediate -iru endings for progressive or perfect tense
+]);
diff --git a/ext/bg/js/dictionary.js b/ext/bg/js/dictionary.js
index 67128725..f5c5b21b 100644
--- a/ext/bg/js/dictionary.js
+++ b/ext/bg/js/dictionary.js
@@ -16,17 +16,21 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiTemplateRender*/
 
 function dictEnabledSet(options) {
-    const dictionaries = {};
-    for (const title in options.dictionaries) {
-        const dictionary = options.dictionaries[title];
-        if (dictionary.enabled) {
-            dictionaries[title] = dictionary;
-        }
+    const enabledDictionaryMap = new Map();
+    const optionsDictionaries = options.dictionaries;
+    for (const title in optionsDictionaries) {
+        if (!hasOwn(optionsDictionaries, title)) { continue; }
+        const dictionary = optionsDictionaries[title];
+        if (!dictionary.enabled) { continue; }
+        enabledDictionaryMap.set(title, {
+            priority: dictionary.priority || 0,
+            allowSecondarySearches: !!dictionary.allowSecondarySearches
+        });
     }
-
-    return dictionaries;
+    return enabledDictionaryMap;
 }
 
 function dictConfigured(options) {
@@ -39,28 +43,15 @@ function dictConfigured(options) {
     return false;
 }
 
-function dictRowsSort(rows, options) {
-    return rows.sort((ra, rb) => {
-        const pa = (options.dictionaries[ra.title] || {}).priority || 0;
-        const pb = (options.dictionaries[rb.title] || {}).priority || 0;
-        if (pa > pb) {
-            return -1;
-        } else if (pa < pb) {
-            return 1;
-        } else {
-            return 0;
-        }
-    });
-}
-
 function dictTermsSort(definitions, dictionaries=null) {
     return definitions.sort((v1, v2) => {
         let i;
         if (dictionaries !== null) {
-            i = (
-                ((dictionaries[v2.dictionary] || {}).priority || 0) -
-                ((dictionaries[v1.dictionary] || {}).priority || 0)
-            );
+            const dictionaryInfo1 = dictionaries.get(v1.dictionary);
+            const dictionaryInfo2 = dictionaries.get(v2.dictionary);
+            const priority1 = typeof dictionaryInfo1 !== 'undefined' ? dictionaryInfo1.priority : 0;
+            const priority2 = typeof dictionaryInfo2 !== 'undefined' ? dictionaryInfo2.priority : 0;
+            i = priority2 - priority1;
             if (i !== 0) { return i; }
         }
 
@@ -78,20 +69,16 @@ function dictTermsSort(definitions, dictionaries=null) {
 }
 
 function dictTermsUndupe(definitions) {
-    const definitionGroups = {};
+    const definitionGroups = new Map();
     for (const definition of definitions) {
-        const definitionExisting = definitionGroups[definition.id];
-        if (!hasOwn(definitionGroups, definition.id) || definition.expression.length > definitionExisting.expression.length) {
-            definitionGroups[definition.id] = definition;
+        const id = definition.id;
+        const definitionExisting = definitionGroups.get(id);
+        if (typeof definitionExisting === 'undefined' || definition.expression.length > definitionExisting.expression.length) {
+            definitionGroups.set(id, definition);
         }
     }
 
-    const definitionsUnique = [];
-    for (const key in definitionGroups) {
-        definitionsUnique.push(definitionGroups[key]);
-    }
-
-    return definitionsUnique;
+    return [...definitionGroups.values()];
 }
 
 function dictTermsCompressTags(definitions) {
@@ -122,35 +109,35 @@ function dictTermsCompressTags(definitions) {
 }
 
 function dictTermsGroup(definitions, dictionaries) {
-    const groups = {};
+    const groups = new Map();
     for (const definition of definitions) {
-        const key = [definition.source, definition.expression];
-        key.push(...definition.reasons);
+        const key = [definition.source, definition.expression, ...definition.reasons];
         if (definition.reading) {
             key.push(definition.reading);
         }
 
         const keyString = key.toString();
-        if (hasOwn(groups, keyString)) {
-            groups[keyString].push(definition);
-        } else {
-            groups[keyString] = [definition];
+        let groupDefinitions = groups.get(keyString);
+        if (typeof groupDefinitions === 'undefined') {
+            groupDefinitions = [];
+            groups.set(keyString, groupDefinitions);
         }
+
+        groupDefinitions.push(definition);
     }
 
     const results = [];
-    for (const key in groups) {
-        const groupDefs = groups[key];
-        const firstDef = groupDefs[0];
-        dictTermsSort(groupDefs, dictionaries);
+    for (const groupDefinitions of groups.values()) {
+        const firstDef = groupDefinitions[0];
+        dictTermsSort(groupDefinitions, dictionaries);
         results.push({
-            definitions: groupDefs,
+            definitions: groupDefinitions,
             expression: firstDef.expression,
             reading: firstDef.reading,
             furiganaSegments: firstDef.furiganaSegments,
             reasons: firstDef.reasons,
             termTags: firstDef.termTags,
-            score: groupDefs.reduce((p, v) => v.score > p ? v.score : p, Number.MIN_SAFE_INTEGER),
+            score: groupDefinitions.reduce((p, v) => v.score > p ? v.score : p, Number.MIN_SAFE_INTEGER),
             source: firstDef.source
         });
     }
@@ -158,14 +145,41 @@ function dictTermsGroup(definitions, dictionaries) {
     return dictTermsSort(results);
 }
 
+function dictAreSetsEqual(set1, set2) {
+    if (set1.size !== set2.size) {
+        return false;
+    }
+
+    for (const value of set1) {
+        if (!set2.has(value)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+function dictGetSetIntersection(set1, set2) {
+    const result = [];
+    for (const value of set1) {
+        if (set2.has(value)) {
+            result.push(value);
+        }
+    }
+    return result;
+}
+
 function dictTermsMergeBySequence(definitions, mainDictionary) {
-    const definitionsBySequence = {'-1': []};
+    const sequencedDefinitions = new Map();
+    const nonSequencedDefinitions = [];
     for (const definition of definitions) {
-        if (mainDictionary === definition.dictionary && definition.sequence >= 0) {
-            if (!definitionsBySequence[definition.sequence]) {
-                definitionsBySequence[definition.sequence] = {
+        const sequence = definition.sequence;
+        if (mainDictionary === definition.dictionary && sequence >= 0) {
+            let sequencedDefinition = sequencedDefinitions.get(sequence);
+            if (typeof sequencedDefinition === 'undefined') {
+                sequencedDefinition = {
                     reasons: definition.reasons,
-                    score: Number.MIN_SAFE_INTEGER,
+                    score: definition.score,
                     expression: new Set(),
                     reading: new Set(),
                     expressions: new Map(),
@@ -173,100 +187,115 @@ function dictTermsMergeBySequence(definitions, mainDictionary) {
                     dictionary: definition.dictionary,
                     definitions: []
                 };
+                sequencedDefinitions.set(sequence, sequencedDefinition);
+            } else {
+                sequencedDefinition.score = Math.max(sequencedDefinition.score, definition.score);
             }
-            const score = Math.max(definitionsBySequence[definition.sequence].score, definition.score);
-            definitionsBySequence[definition.sequence].score = score;
         } else {
-            definitionsBySequence['-1'].push(definition);
+            nonSequencedDefinitions.push(definition);
         }
     }
 
-    return definitionsBySequence;
+    return [sequencedDefinitions, nonSequencedDefinitions];
 }
 
-function dictTermsMergeByGloss(result, definitions, appendTo, mergedIndices) {
-    const definitionsByGloss = appendTo || {};
-    for (const [index, definition] of definitions.entries()) {
-        if (appendTo) {
-            let match = false;
-            for (const expression of result.expressions.keys()) {
-                if (definition.expression === expression) {
-                    for (const reading of result.expressions.get(expression).keys()) {
-                        if (definition.reading === reading) {
-                            match = true;
-                            break;
-                        }
-                    }
-                }
-                if (match) {
-                    break;
-                }
-            }
+function dictTermsMergeByGloss(result, definitions, appendTo=null, mergedIndices=null) {
+    const definitionsByGloss = appendTo !== null ? appendTo : new Map();
 
-            if (!match) {
-                continue;
-            } else if (mergedIndices) {
+    const resultExpressionsMap = result.expressions;
+    const resultExpressionSet = result.expression;
+    const resultReadingSet = result.reading;
+    const resultSource = result.source;
+
+    for (const [index, definition] of definitions.entries()) {
+        const {expression, reading} = definition;
+
+        if (mergedIndices !== null) {
+            const expressionMap = resultExpressionsMap.get(expression);
+            if (
+                typeof expressionMap !== 'undefined' &&
+                typeof expressionMap.get(reading) !== 'undefined'
+            ) {
                 mergedIndices.add(index);
+            } else {
+                continue;
             }
         }
 
         const gloss = JSON.stringify(definition.glossary.concat(definition.dictionary));
-        if (!definitionsByGloss[gloss]) {
-            definitionsByGloss[gloss] = {
+        let glossDefinition = definitionsByGloss.get(gloss);
+        if (typeof glossDefinition === 'undefined') {
+            glossDefinition = {
                 expression: new Set(),
                 reading: new Set(),
                 definitionTags: [],
                 glossary: definition.glossary,
-                source: result.source,
+                source: resultSource,
                 reasons: [],
                 score: definition.score,
                 id: definition.id,
                 dictionary: definition.dictionary
             };
+            definitionsByGloss.set(gloss, glossDefinition);
         }
 
-        definitionsByGloss[gloss].expression.add(definition.expression);
-        definitionsByGloss[gloss].reading.add(definition.reading);
+        glossDefinition.expression.add(expression);
+        glossDefinition.reading.add(reading);
 
-        result.expression.add(definition.expression);
-        result.reading.add(definition.reading);
+        resultExpressionSet.add(expression);
+        resultReadingSet.add(reading);
 
         for (const tag of definition.definitionTags) {
-            if (!definitionsByGloss[gloss].definitionTags.find((existingTag) => existingTag.name === tag.name)) {
-                definitionsByGloss[gloss].definitionTags.push(tag);
+            if (!glossDefinition.definitionTags.find((existingTag) => existingTag.name === tag.name)) {
+                glossDefinition.definitionTags.push(tag);
             }
         }
 
-        if (!appendTo) {
-            // result->expressions[ Expression1[ Reading1[ Tag1, Tag2 ] ], Expression2, ... ]
-            if (!result.expressions.has(definition.expression)) {
-                result.expressions.set(definition.expression, new Map());
+        if (appendTo === null) {
+            /*
+                Data layout:
+                resultExpressionsMap = new Map([
+                    [expression, new Map([
+                        [reading, new Map([
+                            [tagName, tagInfo],
+                            ...
+                        ])],
+                        ...
+                    ])],
+                    ...
+                ]);
+            */
+            let readingMap = resultExpressionsMap.get(expression);
+            if (typeof readingMap === 'undefined') {
+                readingMap = new Map();
+                resultExpressionsMap.set(expression, readingMap);
             }
-            if (!result.expressions.get(definition.expression).has(definition.reading)) {
-                result.expressions.get(definition.expression).set(definition.reading, []);
+
+            let termTagsMap = readingMap.get(reading);
+            if (typeof termTagsMap === 'undefined') {
+                termTagsMap = new Map();
+                readingMap.set(reading, termTagsMap);
             }
 
             for (const tag of definition.termTags) {
-                if (!result.expressions.get(definition.expression).get(definition.reading).find((existingTag) => existingTag.name === tag.name)) {
-                    result.expressions.get(definition.expression).get(definition.reading).push(tag);
+                if (!termTagsMap.has(tag.name)) {
+                    termTagsMap.set(tag.name, tag);
                 }
             }
         }
     }
 
-    for (const gloss in definitionsByGloss) {
-        const definition = definitionsByGloss[gloss];
-        definition.only = [];
-        if (!utilSetEqual(definition.expression, result.expression)) {
-            for (const expression of utilSetIntersection(definition.expression, result.expression)) {
-                definition.only.push(expression);
-            }
+    for (const definition of definitionsByGloss.values()) {
+        const only = [];
+        const expressionSet = definition.expression;
+        const readingSet = definition.reading;
+        if (!dictAreSetsEqual(expressionSet, resultExpressionSet)) {
+            only.push(...dictGetSetIntersection(expressionSet, resultExpressionSet));
         }
-        if (!utilSetEqual(definition.reading, result.reading)) {
-            for (const reading of utilSetIntersection(definition.reading, result.reading)) {
-                definition.only.push(reading);
-            }
+        if (!dictAreSetsEqual(readingSet, resultReadingSet)) {
+            only.push(...dictGetSetIntersection(readingSet, resultReadingSet));
         }
+        definition.only = only;
     }
 
     return definitionsByGloss;
@@ -330,7 +359,7 @@ async function dictFieldFormat(field, definition, mode, options, templates, exce
         }
         data.marker = marker;
         try {
-            return await apiTemplateRender(templates, data, true);
+            return await apiTemplateRender(templates, data);
         } catch (e) {
             if (exceptions) { exceptions.push(e); }
             return `{${marker}-render-error}`;
diff --git a/ext/bg/js/handlebars.js b/ext/bg/js/handlebars.js
index 62f89ee4..b1443447 100644
--- a/ext/bg/js/handlebars.js
+++ b/ext/bg/js/handlebars.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global jpIsCharCodeKanji, jpDistributeFurigana, Handlebars*/
 
 function handlebarsEscape(text) {
     return Handlebars.Utils.escapeExpression(text);
@@ -134,11 +135,6 @@ function handlebarsRegisterHelpers() {
     }
 }
 
-function handlebarsRenderStatic(name, data) {
-    handlebarsRegisterHelpers();
-    return Handlebars.templates[name](data).trim();
-}
-
 function handlebarsRenderDynamic(template, data) {
     handlebarsRegisterHelpers();
     const cache = handlebarsRenderDynamic._cache;
diff --git a/ext/bg/js/japanese.js b/ext/bg/js/japanese.js
new file mode 100644
index 00000000..abb32da4
--- /dev/null
+++ b/ext/bg/js/japanese.js
@@ -0,0 +1,455 @@
+/*
+ * Copyright (C) 2016-2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*global wanakana*/
+
+const JP_HALFWIDTH_KATAKANA_MAPPING = new Map([
+    ['ｦ', 'ヲヺ-'],
+    ['ｧ', 'ァ--'],
+    ['ｨ', 'ィ--'],
+    ['ｩ', 'ゥ--'],
+    ['ｪ', 'ェ--'],
+    ['ｫ', 'ォ--'],
+    ['ｬ', 'ャ--'],
+    ['ｭ', 'ュ--'],
+    ['ｮ', 'ョ--'],
+    ['ｯ', 'ッ--'],
+    ['ｰ', 'ー--'],
+    ['ｱ', 'ア--'],
+    ['ｲ', 'イ--'],
+    ['ｳ', 'ウヴ-'],
+    ['ｴ', 'エ--'],
+    ['ｵ', 'オ--'],
+    ['ｶ', 'カガ-'],
+    ['ｷ', 'キギ-'],
+    ['ｸ', 'クグ-'],
+    ['ｹ', 'ケゲ-'],
+    ['ｺ', 'コゴ-'],
+    ['ｻ', 'サザ-'],
+    ['ｼ', 'シジ-'],
+    ['ｽ', 'スズ-'],
+    ['ｾ', 'セゼ-'],
+    ['ｿ', 'ソゾ-'],
+    ['ﾀ', 'タダ-'],
+    ['ﾁ', 'チヂ-'],
+    ['ﾂ', 'ツヅ-'],
+    ['ﾃ', 'テデ-'],
+    ['ﾄ', 'トド-'],
+    ['ﾅ', 'ナ--'],
+    ['ﾆ', 'ニ--'],
+    ['ﾇ', 'ヌ--'],
+    ['ﾈ', 'ネ--'],
+    ['ﾉ', 'ノ--'],
+    ['ﾊ', 'ハバパ'],
+    ['ﾋ', 'ヒビピ'],
+    ['ﾌ', 'フブプ'],
+    ['ﾍ', 'ヘベペ'],
+    ['ﾎ', 'ホボポ'],
+    ['ﾏ', 'マ--'],
+    ['ﾐ', 'ミ--'],
+    ['ﾑ', 'ム--'],
+    ['ﾒ', 'メ--'],
+    ['ﾓ', 'モ--'],
+    ['ﾔ', 'ヤ--'],
+    ['ﾕ', 'ユ--'],
+    ['ﾖ', 'ヨ--'],
+    ['ﾗ', 'ラ--'],
+    ['ﾘ', 'リ--'],
+    ['ﾙ', 'ル--'],
+    ['ﾚ', 'レ--'],
+    ['ﾛ', 'ロ--'],
+    ['ﾜ', 'ワ--'],
+    ['ﾝ', 'ン--']
+]);
+
+const JP_HIRAGANA_RANGE = [0x3040, 0x309f];
+const JP_KATAKANA_RANGE = [0x30a0, 0x30ff];
+const JP_KANA_RANGES = [JP_HIRAGANA_RANGE, JP_KATAKANA_RANGE];
+
+const JP_CJK_COMMON_RANGE = [0x4e00, 0x9fff];
+const JP_CJK_RARE_RANGE = [0x3400, 0x4dbf];
+const JP_CJK_RANGES = [JP_CJK_COMMON_RANGE, JP_CJK_RARE_RANGE];
+
+const JP_ITERATION_MARK_CHAR_CODE = 0x3005;
+
+// Japanese character ranges, roughly ordered in order of expected frequency
+const JP_JAPANESE_RANGES = [
+    JP_HIRAGANA_RANGE,
+    JP_KATAKANA_RANGE,
+
+    JP_CJK_COMMON_RANGE,
+    JP_CJK_RARE_RANGE,
+
+    [0xff66, 0xff9f], // Halfwidth katakana
+
+    [0x30fb, 0x30fc], // Katakana punctuation
+    [0xff61, 0xff65], // Kana punctuation
+    [0x3000, 0x303f], // CJK punctuation
+
+    [0xff10, 0xff19], // Fullwidth numbers
+    [0xff21, 0xff3a], // Fullwidth upper case Latin letters
+    [0xff41, 0xff5a], // Fullwidth lower case Latin letters
+
+    [0xff01, 0xff0f], // Fullwidth punctuation 1
+    [0xff1a, 0xff1f], // Fullwidth punctuation 2
+    [0xff3b, 0xff3f], // Fullwidth punctuation 3
+    [0xff5b, 0xff60], // Fullwidth punctuation 4
+    [0xffe0, 0xffee]  // Currency markers
+];
+
+
+// Helper functions
+
+function _jpIsCharCodeInRanges(charCode, ranges) {
+    for (const [min, max] of ranges) {
+        if (charCode >= min && charCode <= max) {
+            return true;
+        }
+    }
+    return false;
+}
+
+
+// Character code testing functions
+
+function jpIsCharCodeKanji(charCode) {
+    return _jpIsCharCodeInRanges(charCode, JP_CJK_RANGES);
+}
+
+function jpIsCharCodeKana(charCode) {
+    return _jpIsCharCodeInRanges(charCode, JP_KANA_RANGES);
+}
+
+function jpIsCharCodeJapanese(charCode) {
+    return _jpIsCharCodeInRanges(charCode, JP_JAPANESE_RANGES);
+}
+
+
+// String testing functions
+
+function jpIsStringEntirelyKana(str) {
+    if (str.length === 0) { return false; }
+    for (let i = 0, ii = str.length; i < ii; ++i) {
+        if (!jpIsCharCodeKana(str.charCodeAt(i))) {
+            return false;
+        }
+    }
+    return true;
+}
+
+function jpIsStringPartiallyJapanese(str) {
+    if (str.length === 0) { return false; }
+    for (let i = 0, ii = str.length; i < ii; ++i) {
+        if (jpIsCharCodeJapanese(str.charCodeAt(i))) {
+            return true;
+        }
+    }
+    return false;
+}
+
+
+// Conversion functions
+
+function jpKatakanaToHiragana(text) {
+    let result = '';
+    for (const c of text) {
+        if (wanakana.isKatakana(c)) {
+            result += wanakana.toHiragana(c);
+        } else {
+            result += c;
+        }
+    }
+
+    return result;
+}
+
+function jpHiraganaToKatakana(text) {
+    let result = '';
+    for (const c of text) {
+        if (wanakana.isHiragana(c)) {
+            result += wanakana.toKatakana(c);
+        } else {
+            result += c;
+        }
+    }
+
+    return result;
+}
+
+function jpToRomaji(text) {
+    return wanakana.toRomaji(text);
+}
+
+function jpConvertReading(expressionFragment, readingFragment, readingMode) {
+    switch (readingMode) {
+        case 'hiragana':
+            return jpKatakanaToHiragana(readingFragment || '');
+        case 'katakana':
+            return jpHiraganaToKatakana(readingFragment || '');
+        case 'romaji':
+            if (readingFragment) {
+                return jpToRomaji(readingFragment);
+            } else {
+                if (jpIsStringEntirelyKana(expressionFragment)) {
+                    return jpToRomaji(expressionFragment);
+                }
+            }
+            return readingFragment;
+        case 'none':
+            return null;
+        default:
+            return readingFragment;
+    }
+}
+
+function jpDistributeFurigana(expression, reading) {
+    const fallback = [{furigana: reading, text: expression}];
+    if (!reading) {
+        return fallback;
+    }
+
+    let isAmbiguous = false;
+    const segmentize = (reading2, groups) => {
+        if (groups.length === 0 || isAmbiguous) {
+            return [];
+        }
+
+        const group = groups[0];
+        if (group.mode === 'kana') {
+            if (jpKatakanaToHiragana(reading2).startsWith(jpKatakanaToHiragana(group.text))) {
+                const readingLeft = reading2.substring(group.text.length);
+                const segs = segmentize(readingLeft, groups.splice(1));
+                if (segs) {
+                    return [{text: group.text}].concat(segs);
+                }
+            }
+        } else {
+            let foundSegments = null;
+            for (let i = reading2.length; i >= group.text.length; --i) {
+                const readingUsed = reading2.substring(0, i);
+                const readingLeft = reading2.substring(i);
+                const segs = segmentize(readingLeft, groups.slice(1));
+                if (segs) {
+                    if (foundSegments !== null) {
+                        // more than one way to segmentize the tail, mark as ambiguous
+                        isAmbiguous = true;
+                        return null;
+                    }
+                    foundSegments = [{text: group.text, furigana: readingUsed}].concat(segs);
+                }
+                // there is only one way to segmentize the last non-kana group
+                if (groups.length === 1) {
+                    break;
+                }
+            }
+            return foundSegments;
+        }
+    };
+
+    const groups = [];
+    let modePrev = null;
+    for (const c of expression) {
+        const charCode = c.charCodeAt(0);
+        const modeCurr = jpIsCharCodeKanji(charCode) || charCode === JP_ITERATION_MARK_CHAR_CODE ? 'kanji' : 'kana';
+        if (modeCurr === modePrev) {
+            groups[groups.length - 1].text += c;
+        } else {
+            groups.push({mode: modeCurr, text: c});
+            modePrev = modeCurr;
+        }
+    }
+
+    const segments = segmentize(reading, groups);
+    if (segments && !isAmbiguous) {
+        return segments;
+    }
+    return fallback;
+}
+
+function jpDistributeFuriganaInflected(expression, reading, source) {
+    const output = [];
+
+    let stemLength = 0;
+    const shortest = Math.min(source.length, expression.length);
+    const sourceHiragana = jpKatakanaToHiragana(source);
+    const expressionHiragana = jpKatakanaToHiragana(expression);
+    while (stemLength < shortest && sourceHiragana[stemLength] === expressionHiragana[stemLength]) {
+        ++stemLength;
+    }
+    const offset = source.length - stemLength;
+
+    const stemExpression = source.substring(0, source.length - offset);
+    const stemReading = reading.substring(
+        0,
+        offset === 0 ? reading.length : reading.length - expression.length + stemLength
+    );
+    for (const segment of jpDistributeFurigana(stemExpression, stemReading)) {
+        output.push(segment);
+    }
+
+    if (stemLength !== source.length) {
+        output.push({text: source.substring(stemLength)});
+    }
+
+    return output;
+}
+
+function jpConvertHalfWidthKanaToFullWidth(text, sourceMapping) {
+    let result = '';
+    const ii = text.length;
+    const hasSourceMapping = Array.isArray(sourceMapping);
+
+    for (let i = 0; i < ii; ++i) {
+        const c = text[i];
+        const mapping = JP_HALFWIDTH_KATAKANA_MAPPING.get(c);
+        if (typeof mapping !== 'string') {
+            result += c;
+            continue;
+        }
+
+        let index = 0;
+        switch (text.charCodeAt(i + 1)) {
+            case 0xff9e: // dakuten
+                index = 1;
+                break;
+            case 0xff9f: // handakuten
+                index = 2;
+                break;
+        }
+
+        let c2 = mapping[index];
+        if (index > 0) {
+            if (c2 === '-') { // invalid
+                index = 0;
+                c2 = mapping[0];
+            } else {
+                ++i;
+            }
+        }
+
+        if (hasSourceMapping && index > 0) {
+            index = result.length;
+            const v = sourceMapping.splice(index + 1, 1)[0];
+            sourceMapping[index] += v;
+        }
+        result += c2;
+    }
+
+    return result;
+}
+
+function jpConvertNumericTofullWidth(text) {
+    let result = '';
+    for (let i = 0, ii = text.length; i < ii; ++i) {
+        let c = text.charCodeAt(i);
+        if (c >= 0x30 && c <= 0x39) { // ['0', '9']
+            c += 0xff10 - 0x30; // 0xff10 = '0' full width
+            result += String.fromCharCode(c);
+        } else {
+            result += text[i];
+        }
+    }
+    return result;
+}
+
+function jpConvertAlphabeticToKana(text, sourceMapping) {
+    let part = '';
+    let result = '';
+    const ii = text.length;
+
+    if (sourceMapping.length === ii) {
+        sourceMapping.length = ii;
+        sourceMapping.fill(1);
+    }
+
+    for (let i = 0; i < ii; ++i) {
+        // Note: 0x61 is the character code for 'a'
+        let c = text.charCodeAt(i);
+        if (c >= 0x41 && c <= 0x5a) { // ['A', 'Z']
+            c += (0x61 - 0x41);
+        } else if (c >= 0x61 && c <= 0x7a) { // ['a', 'z']
+            // NOP; c += (0x61 - 0x61);
+        } else if (c >= 0xff21 && c <= 0xff3a) { // ['A', 'Z'] fullwidth
+            c += (0x61 - 0xff21);
+        } else if (c >= 0xff41 && c <= 0xff5a) { // ['a', 'z'] fullwidth
+            c += (0x61 - 0xff41);
+        } else if (c === 0x2d || c === 0xff0d) { // '-' or fullwidth dash
+            c = 0x2d; // '-'
+        } else {
+            if (part.length > 0) {
+                result += jpToHiragana(part, sourceMapping, result.length);
+                part = '';
+            }
+            result += text[i];
+            continue;
+        }
+        part += String.fromCharCode(c);
+    }
+
+    if (part.length > 0) {
+        result += jpToHiragana(part, sourceMapping, result.length);
+    }
+    return result;
+}
+
+function jpToHiragana(text, sourceMapping, sourceMappingStart) {
+    const result = wanakana.toHiragana(text);
+
+    // Generate source mapping
+    if (Array.isArray(sourceMapping)) {
+        if (typeof sourceMappingStart !== 'number') { sourceMappingStart = 0; }
+        let i = 0;
+        let resultPos = 0;
+        const ii = text.length;
+        while (i < ii) {
+            // Find smallest matching substring
+            let iNext = i + 1;
+            let resultPosNext = result.length;
+            while (iNext < ii) {
+                const t = wanakana.toHiragana(text.substring(0, iNext));
+                if (t === result.substring(0, t.length)) {
+                    resultPosNext = t.length;
+                    break;
+                }
+                ++iNext;
+            }
+
+            // Merge characters
+            const removals = iNext - i - 1;
+            if (removals > 0) {
+                let sum = 0;
+                const vs = sourceMapping.splice(sourceMappingStart + 1, removals);
+                for (const v of vs) { sum += v; }
+                sourceMapping[sourceMappingStart] += sum;
+            }
+            ++sourceMappingStart;
+
+            // Empty elements
+            const additions = resultPosNext - resultPos - 1;
+            for (let j = 0; j < additions; ++j) {
+                sourceMapping.splice(sourceMappingStart, 0, 0);
+                ++sourceMappingStart;
+            }
+
+            i = iNext;
+            resultPos = resultPosNext;
+        }
+    }
+
+    return result;
+}
diff --git a/ext/bg/js/json-schema.js b/ext/bg/js/json-schema.js
index 5d596a8b..58f804fd 100644
--- a/ext/bg/js/json-schema.js
+++ b/ext/bg/js/json-schema.js
@@ -64,7 +64,7 @@ class JsonSchemaProxyHandler {
             }
         }
 
-        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property);
+        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property, target);
         if (propertySchema === null) {
             return;
         }
@@ -86,17 +86,14 @@ class JsonSchemaProxyHandler {
             }
         }
 
-        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property);
+        const propertySchema = JsonSchemaProxyHandler.getPropertySchema(this._schema, property, target);
         if (propertySchema === null) {
             throw new Error(`Property ${property} not supported`);
         }
 
         value = JsonSchema.isolate(value);
 
-        const error = JsonSchemaProxyHandler.validate(value, propertySchema);
-        if (error !== null) {
-            throw new Error(`Invalid value: ${error}`);
-        }
+        JsonSchemaProxyHandler.validate(value, propertySchema, new JsonSchemaTraversalInfo(value, propertySchema));
 
         target[property] = value;
         return true;
@@ -122,151 +119,329 @@ class JsonSchemaProxyHandler {
         throw new Error('construct not supported');
     }
 
-    static getPropertySchema(schema, property) {
-        const type = schema.type;
-        if (Array.isArray(type)) {
-            throw new Error(`Ambiguous property type for ${property}`);
-        }
+    static getPropertySchema(schema, property, value, path=null) {
+        const type = JsonSchemaProxyHandler.getSchemaOrValueType(schema, value);
         switch (type) {
             case 'object':
             {
                 const properties = schema.properties;
-                if (properties !== null && typeof properties === 'object' && !Array.isArray(properties)) {
-                    if (Object.prototype.hasOwnProperty.call(properties, property)) {
-                        return properties[property];
+                if (JsonSchemaProxyHandler.isObject(properties)) {
+                    const propertySchema = properties[property];
+                    if (JsonSchemaProxyHandler.isObject(propertySchema)) {
+                        if (path !== null) { path.push(['properties', properties], [property, propertySchema]); }
+                        return propertySchema;
                     }
                 }
 
                 const additionalProperties = schema.additionalProperties;
-                return (additionalProperties !== null && typeof additionalProperties === 'object' && !Array.isArray(additionalProperties)) ? additionalProperties : null;
+                if (additionalProperties === false) {
+                    return null;
+                } else if (JsonSchemaProxyHandler.isObject(additionalProperties)) {
+                    if (path !== null) { path.push(['additionalProperties', additionalProperties]); }
+                    return additionalProperties;
+                } else {
+                    const result = JsonSchemaProxyHandler._unconstrainedSchema;
+                    if (path !== null) { path.push([null, result]); }
+                    return result;
+                }
             }
             case 'array':
             {
                 const items = schema.items;
-                return (items !== null && typeof items === 'object' && !Array.isArray(items)) ? items : null;
+                if (JsonSchemaProxyHandler.isObject(items)) {
+                    return items;
+                }
+                if (Array.isArray(items)) {
+                    if (property >= 0 && property < items.length) {
+                        const propertySchema = items[property];
+                        if (JsonSchemaProxyHandler.isObject(propertySchema)) {
+                            if (path !== null) { path.push(['items', items], [property, propertySchema]); }
+                            return propertySchema;
+                        }
+                    }
+                }
+
+                const additionalItems = schema.additionalItems;
+                if (additionalItems === false) {
+                    return null;
+                } else if (JsonSchemaProxyHandler.isObject(additionalItems)) {
+                    if (path !== null) { path.push(['additionalItems', additionalItems]); }
+                    return additionalItems;
+                } else {
+                    const result = JsonSchemaProxyHandler._unconstrainedSchema;
+                    if (path !== null) { path.push([null, result]); }
+                    return result;
+                }
             }
             default:
                 return null;
         }
     }
 
-    static validate(value, schema) {
+    static getSchemaOrValueType(schema, value) {
+        const type = schema.type;
+
+        if (Array.isArray(type)) {
+            if (typeof value !== 'undefined') {
+                const valueType = JsonSchemaProxyHandler.getValueType(value);
+                if (type.indexOf(valueType) >= 0) {
+                    return valueType;
+                }
+            }
+            return null;
+        }
+
+        if (typeof type === 'undefined') {
+            if (typeof value !== 'undefined') {
+                return JsonSchemaProxyHandler.getValueType(value);
+            }
+            return null;
+        }
+
+        return type;
+    }
+
+    static validate(value, schema, info) {
+        JsonSchemaProxyHandler.validateSingleSchema(value, schema, info);
+        JsonSchemaProxyHandler.validateConditional(value, schema, info);
+        JsonSchemaProxyHandler.validateAllOf(value, schema, info);
+        JsonSchemaProxyHandler.validateAnyOf(value, schema, info);
+        JsonSchemaProxyHandler.validateOneOf(value, schema, info);
+        JsonSchemaProxyHandler.validateNoneOf(value, schema, info);
+    }
+
+    static validateConditional(value, schema, info) {
+        const ifSchema = schema.if;
+        if (!JsonSchemaProxyHandler.isObject(ifSchema)) { return; }
+
+        let okay = true;
+        info.schemaPush('if', ifSchema);
+        try {
+            JsonSchemaProxyHandler.validate(value, ifSchema, info);
+        } catch (e) {
+            okay = false;
+        }
+        info.schemaPop();
+
+        const nextSchema = okay ? schema.then : schema.else;
+        if (JsonSchemaProxyHandler.isObject(nextSchema)) {
+            info.schemaPush(okay ? 'then' : 'else', nextSchema);
+            JsonSchemaProxyHandler.validate(value, nextSchema, info);
+            info.schemaPop();
+        }
+    }
+
+    static validateAllOf(value, schema, info) {
+        const subSchemas = schema.allOf;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('allOf', subSchemas);
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            JsonSchemaProxyHandler.validate(value, subSchema, info);
+            info.schemaPop();
+        }
+        info.schemaPop();
+    }
+
+    static validateAnyOf(value, schema, info) {
+        const subSchemas = schema.anyOf;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('anyOf', subSchemas);
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            try {
+                JsonSchemaProxyHandler.validate(value, subSchema, info);
+                return;
+            } catch (e) {
+                // NOP
+            }
+            info.schemaPop();
+        }
+
+        throw new JsonSchemaValidationError('0 anyOf schemas matched', value, schema, info);
+        // info.schemaPop(); // Unreachable
+    }
+
+    static validateOneOf(value, schema, info) {
+        const subSchemas = schema.oneOf;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('oneOf', subSchemas);
+        let count = 0;
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            try {
+                JsonSchemaProxyHandler.validate(value, subSchema, info);
+                ++count;
+            } catch (e) {
+                // NOP
+            }
+            info.schemaPop();
+        }
+
+        if (count !== 1) {
+            throw new JsonSchemaValidationError(`${count} oneOf schemas matched`, value, schema, info);
+        }
+
+        info.schemaPop();
+    }
+
+    static validateNoneOf(value, schema, info) {
+        const subSchemas = schema.not;
+        if (!Array.isArray(subSchemas)) { return; }
+
+        info.schemaPush('not', subSchemas);
+        for (let i = 0; i < subSchemas.length; ++i) {
+            const subSchema = subSchemas[i];
+            info.schemaPush(i, subSchema);
+            try {
+                JsonSchemaProxyHandler.validate(value, subSchema, info);
+            } catch (e) {
+                info.schemaPop();
+                continue;
+            }
+            throw new JsonSchemaValidationError(`not[${i}] schema matched`, value, schema, info);
+        }
+        info.schemaPop();
+    }
+
+    static validateSingleSchema(value, schema, info) {
         const type = JsonSchemaProxyHandler.getValueType(value);
         const schemaType = schema.type;
         if (!JsonSchemaProxyHandler.isValueTypeAny(value, type, schemaType)) {
-            return `Value type ${type} does not match schema type ${schemaType}`;
+            throw new JsonSchemaValidationError(`Value type ${type} does not match schema type ${schemaType}`, value, schema, info);
         }
 
         const schemaEnum = schema.enum;
         if (Array.isArray(schemaEnum) && !JsonSchemaProxyHandler.valuesAreEqualAny(value, schemaEnum)) {
-            return 'Invalid enum value';
+            throw new JsonSchemaValidationError('Invalid enum value', value, schema, info);
         }
 
         switch (type) {
             case 'number':
-                return JsonSchemaProxyHandler.validateNumber(value, schema);
+                JsonSchemaProxyHandler.validateNumber(value, schema, info);
+                break;
             case 'string':
-                return JsonSchemaProxyHandler.validateString(value, schema);
+                JsonSchemaProxyHandler.validateString(value, schema, info);
+                break;
             case 'array':
-                return JsonSchemaProxyHandler.validateArray(value, schema);
+                JsonSchemaProxyHandler.validateArray(value, schema, info);
+                break;
             case 'object':
-                return JsonSchemaProxyHandler.validateObject(value, schema);
-            default:
-                return null;
+                JsonSchemaProxyHandler.validateObject(value, schema, info);
+                break;
         }
     }
 
-    static validateNumber(value, schema) {
+    static validateNumber(value, schema, info) {
         const multipleOf = schema.multipleOf;
         if (typeof multipleOf === 'number' && Math.floor(value / multipleOf) * multipleOf !== value) {
-            return `Number is not a multiple of ${multipleOf}`;
+            throw new JsonSchemaValidationError(`Number is not a multiple of ${multipleOf}`, value, schema, info);
         }
 
         const minimum = schema.minimum;
         if (typeof minimum === 'number' && value < minimum) {
-            return `Number is less than ${minimum}`;
+            throw new JsonSchemaValidationError(`Number is less than ${minimum}`, value, schema, info);
         }
 
         const exclusiveMinimum = schema.exclusiveMinimum;
         if (typeof exclusiveMinimum === 'number' && value <= exclusiveMinimum) {
-            return `Number is less than or equal to ${exclusiveMinimum}`;
+            throw new JsonSchemaValidationError(`Number is less than or equal to ${exclusiveMinimum}`, value, schema, info);
         }
 
         const maximum = schema.maximum;
         if (typeof maximum === 'number' && value > maximum) {
-            return `Number is greater than ${maximum}`;
+            throw new JsonSchemaValidationError(`Number is greater than ${maximum}`, value, schema, info);
         }
 
         const exclusiveMaximum = schema.exclusiveMaximum;
         if (typeof exclusiveMaximum === 'number' && value >= exclusiveMaximum) {
-            return `Number is greater than or equal to ${exclusiveMaximum}`;
+            throw new JsonSchemaValidationError(`Number is greater than or equal to ${exclusiveMaximum}`, value, schema, info);
         }
-
-        return null;
     }
 
-    static validateString(value, schema) {
+    static validateString(value, schema, info) {
         const minLength = schema.minLength;
         if (typeof minLength === 'number' && value.length < minLength) {
-            return 'String length too short';
+            throw new JsonSchemaValidationError('String length too short', value, schema, info);
         }
 
-        const maxLength = schema.minLength;
+        const maxLength = schema.maxLength;
         if (typeof maxLength === 'number' && value.length > maxLength) {
-            return 'String length too long';
+            throw new JsonSchemaValidationError('String length too long', value, schema, info);
         }
-
-        return null;
     }
 
-    static validateArray(value, schema) {
+    static validateArray(value, schema, info) {
         const minItems = schema.minItems;
         if (typeof minItems === 'number' && value.length < minItems) {
-            return 'Array length too short';
+            throw new JsonSchemaValidationError('Array length too short', value, schema, info);
         }
 
         const maxItems = schema.maxItems;
         if (typeof maxItems === 'number' && value.length > maxItems) {
-            return 'Array length too long';
+            throw new JsonSchemaValidationError('Array length too long', value, schema, info);
         }
 
-        return null;
+        for (let i = 0, ii = value.length; i < ii; ++i) {
+            const schemaPath = [];
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, i, value, schemaPath);
+            if (propertySchema === null) {
+                throw new JsonSchemaValidationError(`No schema found for array[${i}]`, value, schema, info);
+            }
+
+            const propertyValue = value[i];
+
+            for (const [p, s] of schemaPath) { info.schemaPush(p, s); }
+            info.valuePush(i, propertyValue);
+            JsonSchemaProxyHandler.validate(propertyValue, propertySchema, info);
+            info.valuePop();
+            for (let j = 0, jj = schemaPath.length; j < jj; ++j) { info.schemaPop(); }
+        }
     }
 
-    static validateObject(value, schema) {
+    static validateObject(value, schema, info) {
         const properties = new Set(Object.getOwnPropertyNames(value));
 
         const required = schema.required;
         if (Array.isArray(required)) {
             for (const property of required) {
                 if (!properties.has(property)) {
-                    return `Missing property ${property}`;
+                    throw new JsonSchemaValidationError(`Missing property ${property}`, value, schema, info);
                 }
             }
         }
 
         const minProperties = schema.minProperties;
         if (typeof minProperties === 'number' && properties.length < minProperties) {
-            return 'Not enough object properties';
+            throw new JsonSchemaValidationError('Not enough object properties', value, schema, info);
         }
 
         const maxProperties = schema.maxProperties;
         if (typeof maxProperties === 'number' && properties.length > maxProperties) {
-            return 'Too many object properties';
+            throw new JsonSchemaValidationError('Too many object properties', value, schema, info);
         }
 
         for (const property of properties) {
-            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property);
+            const schemaPath = [];
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property, value, schemaPath);
             if (propertySchema === null) {
-                return `No schema found for ${property}`;
-            }
-            const error = JsonSchemaProxyHandler.validate(value[property], propertySchema);
-            if (error !== null) {
-                return error;
+                throw new JsonSchemaValidationError(`No schema found for ${property}`, value, schema, info);
             }
-        }
 
-        return null;
+            const propertyValue = value[property];
+
+            for (const [p, s] of schemaPath) { info.schemaPush(p, s); }
+            info.valuePush(property, propertyValue);
+            JsonSchemaProxyHandler.validate(propertyValue, propertySchema, info);
+            info.valuePop();
+            for (let i = 0; i < schemaPath.length; ++i) { info.schemaPop(); }
+        }
     }
 
     static isValueTypeAny(value, type, schemaTypes) {
@@ -372,14 +547,14 @@ class JsonSchemaProxyHandler {
             for (const property of required) {
                 properties.delete(property);
 
-                const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property);
+                const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property, value);
                 if (propertySchema === null) { continue; }
                 value[property] = JsonSchemaProxyHandler.getValidValueOrDefault(propertySchema, value[property]);
             }
         }
 
         for (const property of properties) {
-            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property);
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, property, value);
             if (propertySchema === null) {
                 Reflect.deleteProperty(value, property);
             } else {
@@ -392,13 +567,53 @@ class JsonSchemaProxyHandler {
 
     static populateArrayDefaults(value, schema) {
         for (let i = 0, ii = value.length; i < ii; ++i) {
-            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, i);
+            const propertySchema = JsonSchemaProxyHandler.getPropertySchema(schema, i, value);
             if (propertySchema === null) { continue; }
             value[i] = JsonSchemaProxyHandler.getValidValueOrDefault(propertySchema, value[i]);
         }
 
         return value;
     }
+
+    static isObject(value) {
+        return typeof value === 'object' && value !== null && !Array.isArray(value);
+    }
+}
+
+JsonSchemaProxyHandler._unconstrainedSchema = {};
+
+class JsonSchemaTraversalInfo {
+    constructor(value, schema) {
+        this.valuePath = [];
+        this.schemaPath = [];
+        this.valuePush(null, value);
+        this.schemaPush(null, schema);
+    }
+
+    valuePush(path, value) {
+        this.valuePath.push([path, value]);
+    }
+
+    valuePop() {
+        this.valuePath.pop();
+    }
+
+    schemaPush(path, schema) {
+        this.schemaPath.push([path, schema]);
+    }
+
+    schemaPop() {
+        this.schemaPath.pop();
+    }
+}
+
+class JsonSchemaValidationError extends Error {
+    constructor(message, value, schema, info) {
+        super(message);
+        this.value = value;
+        this.schema = schema;
+        this.info = info;
+    }
 }
 
 class JsonSchema {
@@ -406,6 +621,10 @@ class JsonSchema {
         return new Proxy(target, new JsonSchemaProxyHandler(schema));
     }
 
+    static validate(value, schema) {
+        return JsonSchemaProxyHandler.validate(value, schema, new JsonSchemaTraversalInfo(value, schema));
+    }
+
     static getValidValueOrDefault(schema, value) {
         return JsonSchemaProxyHandler.getValidValueOrDefault(schema, value);
     }
diff --git a/ext/bg/js/options.js b/ext/bg/js/options.js
index d93862bf..f9db99a2 100644
--- a/ext/bg/js/options.js
+++ b/ext/bg/js/options.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global utilStringHashCode*/
 
 /*
  * Generic options functions
@@ -266,6 +267,7 @@ function profileOptionsCreateDefaults() {
     return {
         general: {
             enable: true,
+            enableClipboardPopups: false,
             resultOutputMode: 'group',
             debugInfo: false,
             maxResults: 32,
@@ -316,7 +318,8 @@ function profileOptionsCreateDefaults() {
             popupNestingMaxDepth: 0,
             enablePopupSearch: false,
             enableOnPopupExpressions: false,
-            enableOnSearchPage: true
+            enableOnSearchPage: true,
+            enableSearchTags: false
         },
 
         translation: {
diff --git a/ext/bg/js/page-exit-prevention.js b/ext/bg/js/page-exit-prevention.js
index 3a320db3..be06c495 100644
--- a/ext/bg/js/page-exit-prevention.js
+++ b/ext/bg/js/page-exit-prevention.js
@@ -18,43 +18,43 @@
 
 
 class PageExitPrevention {
-  constructor() {
-  }
-
-  start() {
-      PageExitPrevention._addInstance(this);
-  }
-
-  end() {
-      PageExitPrevention._removeInstance(this);
-  }
-
-  static _addInstance(instance) {
-      const size = PageExitPrevention._instances.size;
-      PageExitPrevention._instances.set(instance, true);
-      if (size === 0) {
-          window.addEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
-      }
-  }
-
-  static _removeInstance(instance) {
-      if (
-          PageExitPrevention._instances.delete(instance) &&
-          PageExitPrevention._instances.size === 0
-      ) {
-          window.removeEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
-      }
-  }
-
-  static _onBeforeUnload(e) {
-      if (PageExitPrevention._instances.size === 0) {
-          return;
-      }
-
-      e.preventDefault();
-      e.returnValue = '';
-      return '';
-  }
+    constructor() {
+    }
+
+    start() {
+        PageExitPrevention._addInstance(this);
+    }
+
+    end() {
+        PageExitPrevention._removeInstance(this);
+    }
+
+    static _addInstance(instance) {
+        const size = PageExitPrevention._instances.size;
+        PageExitPrevention._instances.set(instance, true);
+        if (size === 0) {
+            window.addEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
+        }
+    }
+
+    static _removeInstance(instance) {
+        if (
+            PageExitPrevention._instances.delete(instance) &&
+            PageExitPrevention._instances.size === 0
+        ) {
+            window.removeEventListener('beforeunload', PageExitPrevention._onBeforeUnload);
+        }
+    }
+
+    static _onBeforeUnload(e) {
+        if (PageExitPrevention._instances.size === 0) {
+            return;
+        }
+
+        e.preventDefault();
+        e.returnValue = '';
+        return '';
+    }
 }
 
 PageExitPrevention._instances = new Map();
diff --git a/ext/bg/js/search-frontend.js b/ext/bg/js/search-frontend.js
index e453ccef..509c4009 100644
--- a/ext/bg/js/search-frontend.js
+++ b/ext/bg/js/search-frontend.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGet*/
 
 async function searchFrontendSetup() {
     const optionsContext = {
diff --git a/ext/bg/js/search-query-parser-generator.js b/ext/bg/js/search-query-parser-generator.js
new file mode 100644
index 00000000..1ab23a82
--- /dev/null
+++ b/ext/bg/js/search-query-parser-generator.js
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*global apiGetQueryParserTemplatesHtml, TemplateHandler*/
+
+class QueryParserGenerator {
+    constructor() {
+        this._templateHandler = null;
+    }
+
+    async prepare() {
+        const html = await apiGetQueryParserTemplatesHtml();
+        this._templateHandler = new TemplateHandler(html);
+    }
+
+    createParseResult(terms, preview=false) {
+        const fragment = document.createDocumentFragment();
+        for (const term of terms) {
+            const termContainer = this._templateHandler.instantiate(preview ? 'term-preview' : 'term');
+            for (const segment of term) {
+                if (!segment.text.trim()) { continue; }
+                if (!segment.reading || !segment.reading.trim()) {
+                    termContainer.appendChild(this.createSegmentText(segment.text));
+                } else {
+                    termContainer.appendChild(this.createSegment(segment));
+                }
+            }
+            fragment.appendChild(termContainer);
+        }
+        return fragment;
+    }
+
+    createSegment(segment) {
+        const segmentContainer = this._templateHandler.instantiate('segment');
+        const segmentTextContainer = segmentContainer.querySelector('.query-parser-segment-text');
+        const segmentReadingContainer = segmentContainer.querySelector('.query-parser-segment-reading');
+        segmentTextContainer.appendChild(this.createSegmentText(segment.text));
+        segmentReadingContainer.textContent = segment.reading;
+        return segmentContainer;
+    }
+
+    createSegmentText(text) {
+        const fragment = document.createDocumentFragment();
+        for (const chr of text) {
+            const charContainer = this._templateHandler.instantiate('char');
+            charContainer.textContent = chr;
+            fragment.appendChild(charContainer);
+        }
+        return fragment;
+    }
+
+    createParserSelect(parseResults, selectedParser) {
+        const selectContainer = this._templateHandler.instantiate('select');
+        for (const parseResult of parseResults) {
+            const optionContainer = this._templateHandler.instantiate('select-option');
+            optionContainer.value = parseResult.id;
+            optionContainer.textContent = parseResult.name;
+            optionContainer.defaultSelected = selectedParser === parseResult.id;
+            selectContainer.appendChild(optionContainer);
+        }
+        return selectContainer;
+    }
+}
diff --git a/ext/bg/js/search-query-parser.js b/ext/bg/js/search-query-parser.js
index e8e6d11f..0d4aaa50 100644
--- a/ext/bg/js/search-query-parser.js
+++ b/ext/bg/js/search-query-parser.js
@@ -16,17 +16,24 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiTermsFind, apiOptionsSet, apiTextParse, apiTextParseMecab, TextScanner, QueryParserGenerator*/
 
 class QueryParser extends TextScanner {
     constructor(search) {
-        super(document.querySelector('#query-parser'), [], [], []);
+        super(document.querySelector('#query-parser-content'), [], [], []);
         this.search = search;
 
         this.parseResults = [];
         this.selectedParser = null;
 
-        this.queryParser = document.querySelector('#query-parser');
-        this.queryParserSelect = document.querySelector('#query-parser-select');
+        this.queryParser = document.querySelector('#query-parser-content');
+        this.queryParserSelect = document.querySelector('#query-parser-select-container');
+
+        this.queryParserGenerator = new QueryParserGenerator();
+    }
+
+    async prepare() {
+        await this.queryParserGenerator.prepare();
     }
 
     onError(error) {
@@ -52,7 +59,7 @@ class QueryParser extends TextScanner {
 
         this.search.setContent('terms', {definitions, context: {
             focus: false,
-            disableHistory: cause === 'mouse' ? true : false,
+            disableHistory: cause === 'mouse',
             sentence: {text: searchText, offset: 0},
             url: window.location.href
         }});
@@ -64,7 +71,7 @@ class QueryParser extends TextScanner {
         const selectedParser = e.target.value;
         this.selectedParser = selectedParser;
         apiOptionsSet({parsing: {selectedParser}}, this.search.getOptionsContext());
-        this.renderParseResult(this.getParseResult());
+        this.renderParseResult();
     }
 
     getMouseEventListeners() {
@@ -113,13 +120,13 @@ class QueryParser extends TextScanner {
     async setText(text) {
         this.search.setSpinnerVisible(true);
 
-        await this.setPreview(text);
+        this.setPreview(text);
 
         this.parseResults = await this.parseText(text);
         this.refreshSelectedParser();
 
         this.renderParserSelect();
-        await this.renderParseResult();
+        this.renderParseResult();
 
         this.search.setSpinnerVisible(false);
     }
@@ -146,57 +153,29 @@ class QueryParser extends TextScanner {
         return results;
     }
 
-    async setPreview(text) {
+    setPreview(text) {
         const previewTerms = [];
         for (let i = 0, ii = text.length; i < ii; i += 2) {
             const tempText = text.substring(i, i + 2);
-            previewTerms.push([{text: tempText.split('')}]);
+            previewTerms.push([{text: tempText}]);
         }
-        this.queryParser.innerHTML = await apiTemplateRender('query-parser.html', {
-            terms: previewTerms,
-            preview: true
-        });
+        this.queryParser.textContent = '';
+        this.queryParser.appendChild(this.queryParserGenerator.createParseResult(previewTerms, true));
     }
 
     renderParserSelect() {
-        this.queryParserSelect.innerHTML = '';
+        this.queryParserSelect.textContent = '';
         if (this.parseResults.length > 1) {
-            const select = document.createElement('select');
-            select.classList.add('form-control');
-            for (const parseResult of this.parseResults) {
-                const option = document.createElement('option');
-                option.value = parseResult.id;
-                option.innerText = parseResult.name;
-                option.defaultSelected = this.selectedParser === parseResult.id;
-                select.appendChild(option);
-            }
+            const select = this.queryParserGenerator.createParserSelect(this.parseResults, this.selectedParser);
             select.addEventListener('change', this.onParserChange.bind(this));
             this.queryParserSelect.appendChild(select);
         }
     }
 
-    async renderParseResult() {
+    renderParseResult() {
         const parseResult = this.getParseResult();
-        if (!parseResult) {
-            this.queryParser.innerHTML = '';
-            return;
-        }
-
-        this.queryParser.innerHTML = await apiTemplateRender(
-            'query-parser.html',
-            {terms: QueryParser.processParseResultForDisplay(parseResult.parsedText)}
-        );
-    }
-
-    static processParseResultForDisplay(result) {
-        return result.map((term) => {
-            return term.filter((part) => part.text.trim()).map((part) => {
-                return {
-                    text: part.text.split(''),
-                    reading: part.reading,
-                    raw: !part.reading || !part.reading.trim()
-                };
-            });
-        });
+        this.queryParser.textContent = '';
+        if (!parseResult) { return; }
+        this.queryParser.appendChild(this.queryParserGenerator.createParseResult(parseResult.parsedText));
     }
 }
diff --git a/ext/bg/js/search.js b/ext/bg/js/search.js
index f5c641a8..98e167ad 100644
--- a/ext/bg/js/search.js
+++ b/ext/bg/js/search.js
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsSet, apiTermsFind, Display, QueryParser, ClipboardMonitor*/
+
 class DisplaySearch extends Display {
     constructor() {
         super(document.querySelector('#spinner'), document.querySelector('#content'));
@@ -36,12 +38,7 @@ class DisplaySearch extends Display {
         this.introVisible = true;
         this.introAnimationTimer = null;
 
-        this.isFirefox = false;
-
-        this.clipboardMonitorTimerId = null;
-        this.clipboardMonitorTimerToken = null;
-        this.clipboardInterval = 250;
-        this.clipboardPreviousText = null;
+        this.clipboardMonitor = new ClipboardMonitor();
     }
 
     static create() {
@@ -52,13 +49,17 @@ class DisplaySearch extends Display {
 
     async prepare() {
         try {
-            await this.initialize();
-            this.isFirefox = await DisplaySearch._isFirefox();
+            const superPromise = super.prepare();
+            const queryParserPromise = this.queryParser.prepare();
+            await Promise.all([superPromise, queryParserPromise]);
+
+            const {queryParams: {query='', mode=''}} = parseUrl(window.location.href);
 
             if (this.search !== null) {
                 this.search.addEventListener('click', (e) => this.onSearch(e), false);
             }
             if (this.query !== null) {
+                document.documentElement.dataset.searchMode = mode;
                 this.query.addEventListener('input', () => this.onSearchInput(), false);
 
                 if (this.wanakanaEnable !== null) {
@@ -69,34 +70,26 @@ class DisplaySearch extends Display {
                         this.wanakanaEnable.checked = false;
                     }
                     this.wanakanaEnable.addEventListener('change', (e) => {
-                        const query = DisplaySearch.getSearchQueryFromLocation(window.location.href) || '';
+                        const {queryParams: {query: query2=''}} = parseUrl(window.location.href);
                         if (e.target.checked) {
                             window.wanakana.bind(this.query);
-                            this.setQuery(window.wanakana.toKana(query));
                             apiOptionsSet({general: {enableWanakana: true}}, this.getOptionsContext());
                         } else {
                             window.wanakana.unbind(this.query);
-                            this.setQuery(query);
                             apiOptionsSet({general: {enableWanakana: false}}, this.getOptionsContext());
                         }
+                        this.setQuery(query2);
                         this.onSearchQueryUpdated(this.query.value, false);
                     });
                 }
 
-                const query = DisplaySearch.getSearchQueryFromLocation(window.location.href);
-                if (query !== null) {
-                    if (this.isWanakanaEnabled()) {
-                        this.setQuery(window.wanakana.toKana(query));
-                    } else {
-                        this.setQuery(query);
-                    }
-                    this.onSearchQueryUpdated(this.query.value, false);
-                }
+                this.setQuery(query);
+                this.onSearchQueryUpdated(this.query.value, false);
             }
-            if (this.clipboardMonitorEnable !== null) {
+            if (this.clipboardMonitorEnable !== null && mode !== 'popup') {
                 if (this.options.general.enableClipboardMonitor === true) {
                     this.clipboardMonitorEnable.checked = true;
-                    this.startClipboardMonitor();
+                    this.clipboardMonitor.start();
                 } else {
                     this.clipboardMonitorEnable.checked = false;
                 }
@@ -106,7 +99,7 @@ class DisplaySearch extends Display {
                             {permissions: ['clipboardRead']},
                             (granted) => {
                                 if (granted) {
-                                    this.startClipboardMonitor();
+                                    this.clipboardMonitor.start();
                                     apiOptionsSet({general: {enableClipboardMonitor: true}}, this.getOptionsContext());
                                 } else {
                                     e.target.checked = false;
@@ -114,16 +107,20 @@ class DisplaySearch extends Display {
                             }
                         );
                     } else {
-                        this.stopClipboardMonitor();
+                        this.clipboardMonitor.stop();
                         apiOptionsSet({general: {enableClipboardMonitor: false}}, this.getOptionsContext());
                     }
                 });
             }
 
+            chrome.runtime.onMessage.addListener(this.onRuntimeMessage.bind(this));
+
             window.addEventListener('popstate', (e) => this.onPopState(e));
+            window.addEventListener('copy', (e) => this.onCopy(e));
+
+            this.clipboardMonitor.onClipboardText = (text) => this.onExternalSearchUpdate(text);
 
             this.updateSearchButton();
-            this.initClipboardMonitor();
         } catch (e) {
             this.onError(e);
         }
@@ -159,25 +156,32 @@ class DisplaySearch extends Display {
         e.preventDefault();
 
         const query = this.query.value;
+
         this.queryParser.setText(query);
-        const queryString = query.length > 0 ? `?query=${encodeURIComponent(query)}` : '';
-        window.history.pushState(null, '', `${window.location.pathname}${queryString}`);
+
+        const url = new URL(window.location.href);
+        url.searchParams.set('query', query);
+        window.history.pushState(null, '', url.toString());
+
         this.onSearchQueryUpdated(query, true);
     }
 
     onPopState() {
-        const query = DisplaySearch.getSearchQueryFromLocation(window.location.href) || '';
-        if (this.query !== null) {
-            if (this.isWanakanaEnabled()) {
-                this.setQuery(window.wanakana.toKana(query));
-            } else {
-                this.setQuery(query);
-            }
-        }
-
+        const {queryParams: {query='', mode=''}} = parseUrl(window.location.href);
+        document.documentElement.dataset.searchMode = mode;
+        this.setQuery(query);
         this.onSearchQueryUpdated(this.query.value, false);
     }
 
+    onRuntimeMessage({action, params}, sender, callback) {
+        const handler = DisplaySearch._runtimeMessageHandlers.get(action);
+        if (typeof handler !== 'function') { return false; }
+
+        const result = handler(this, params, sender);
+        callback(result);
+        return false;
+    }
+
     onKeyDown(e) {
         const key = Display.getKeyFromEvent(e);
         const ignoreKeys = DisplaySearch.onKeyDownIgnoreKeys;
@@ -202,6 +206,19 @@ class DisplaySearch extends Display {
         }
     }
 
+    onCopy() {
+        // ignore copy from search page
+        this.clipboardMonitor.setPreviousText(document.getSelection().toString().trim());
+    }
+
+    onExternalSearchUpdate(text) {
+        this.setQuery(text);
+        const url = new URL(window.location.href);
+        url.searchParams.set('query', text);
+        window.history.pushState(null, '', url.toString());
+        this.onSearchQueryUpdated(this.query.value, true);
+    }
+
     async onSearchQueryUpdated(query, animate) {
         try {
             const details = {};
@@ -241,74 +258,6 @@ class DisplaySearch extends Display {
         this.queryParser.setOptions(this.options);
     }
 
-    initClipboardMonitor() {
-        // ignore copy from search page
-        window.addEventListener('copy', () => {
-            this.clipboardPreviousText = document.getSelection().toString().trim();
-        });
-    }
-
-    startClipboardMonitor() {
-        // The token below is used as a unique identifier to ensure that a new clipboard monitor
-        // hasn't been started during the await call. The check below the await this.getClipboardText()
-        // call will exit early if the reference has changed.
-        const token = {};
-        const intervalCallback = async () => {
-            this.clipboardMonitorTimerId = null;
-
-            let text = await this.getClipboardText();
-            if (this.clipboardMonitorTimerToken !== token) { return; }
-
-            if (
-                typeof text === 'string' &&
-                (text = text.trim()).length > 0 &&
-                text !== this.clipboardPreviousText
-            ) {
-                this.clipboardPreviousText = text;
-                if (jpIsStringPartiallyJapanese(text)) {
-                    this.setQuery(this.isWanakanaEnabled() ? window.wanakana.toKana(text) : text);
-                    window.history.pushState(null, '', `${window.location.pathname}?query=${encodeURIComponent(text)}`);
-                    this.onSearchQueryUpdated(this.query.value, true);
-                }
-            }
-
-            this.clipboardMonitorTimerId = setTimeout(intervalCallback, this.clipboardInterval);
-        };
-
-        this.clipboardMonitorTimerToken = token;
-
-        intervalCallback();
-    }
-
-    stopClipboardMonitor() {
-        this.clipboardMonitorTimerToken = null;
-        if (this.clipboardMonitorTimerId !== null) {
-            clearTimeout(this.clipboardMonitorTimerId);
-            this.clipboardMonitorTimerId = null;
-        }
-    }
-
-    async getClipboardText() {
-        /*
-        Notes:
-            apiClipboardGet doesn't work on Firefox because document.execCommand('paste')
-            results in an empty string on the web extension background page.
-            This may be a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985
-            Therefore, navigator.clipboard.readText() is used on Firefox.
-
-            navigator.clipboard.readText() can't be used in Chrome for two reasons:
-            * Requires page to be focused, else it rejects with an exception.
-            * When the page is focused, Chrome will request clipboard permission, despite already
-              being an extension with clipboard permissions. It effectively asks for the
-              non-extension permission for clipboard access.
-        */
-        try {
-            return this.isFirefox ? await navigator.clipboard.readText() : await apiClipboardGet();
-        } catch (e) {
-            return null;
-        }
-    }
-
     isWanakanaEnabled() {
         return this.wanakanaEnable !== null && this.wanakanaEnable.checked;
     }
@@ -318,8 +267,9 @@ class DisplaySearch extends Display {
     }
 
     setQuery(query) {
-        this.query.value = query;
-        this.queryParser.setText(query);
+        const interpretedQuery = this.isWanakanaEnabled() ? window.wanakana.toKana(query) : query;
+        this.query.value = interpretedQuery;
+        this.queryParser.setText(interpretedQuery);
     }
 
     setIntroVisible(visible, animate) {
@@ -394,22 +344,6 @@ class DisplaySearch extends Display {
             document.title = `${text} - Yomichan Search`;
         }
     }
-
-    static getSearchQueryFromLocation(url) {
-        const match = /^[^?#]*\?(?:[^&#]*&)?query=([^&#]*)/.exec(url);
-        return match !== null ? decodeURIComponent(match[1]) : null;
-    }
-
-    static async _isFirefox() {
-        const {browser} = await apiGetEnvironmentInfo();
-        switch (browser) {
-            case 'firefox':
-            case 'firefox-mobile':
-                return true;
-            default:
-                return false;
-        }
-    }
 }
 
 DisplaySearch.onKeyDownIgnoreKeys = {
@@ -427,4 +361,8 @@ DisplaySearch.onKeyDownIgnoreKeys = {
     'Shift': []
 };
 
+DisplaySearch._runtimeMessageHandlers = new Map([
+    ['searchQueryUpdate', (self, {query}) => { self.onExternalSearchUpdate(query); }]
+]);
+
 DisplaySearch.instance = DisplaySearch.create();
diff --git a/ext/bg/js/settings/anki-templates.js b/ext/bg/js/settings/anki-templates.js
index 5e74358f..2e80e334 100644
--- a/ext/bg/js/settings/anki-templates.js
+++ b/ext/bg/js/settings/anki-templates.js
@@ -16,6 +16,9 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, settingsSaveOptions
+profileOptionsGetDefaultFieldTemplates, ankiGetFieldMarkers, ankiGetFieldMarkersHtml, dictFieldFormat
+apiOptionsGet, apiTermsFind*/
 
 function onAnkiFieldTemplatesReset(e) {
     e.preventDefault();
diff --git a/ext/bg/js/settings/anki.js b/ext/bg/js/settings/anki.js
index 9adb2f2a..4263fc51 100644
--- a/ext/bg/js/settings/anki.js
+++ b/ext/bg/js/settings/anki.js
@@ -16,6 +16,9 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, settingsSaveOptions
+utilBackgroundIsolate, utilAnkiGetDeckNames, utilAnkiGetModelNames, utilAnkiGetModelFieldNames
+onFormOptionsChanged*/
 
 // Private
 
@@ -33,14 +36,27 @@ function _ankiSpinnerShow(show) {
 
 function _ankiSetError(error) {
     const node = document.querySelector('#anki-error');
-    if (!node) { return; }
+    const node2 = document.querySelector('#anki-invalid-response-error');
     if (error) {
-        node.hidden = false;
-        node.textContent = `${error}`;
-        _ankiSetErrorData(node, error);
+        const errorString = `${error}`;
+        if (node !== null) {
+            node.hidden = false;
+            node.textContent = errorString;
+            _ankiSetErrorData(node, error);
+        }
+
+        if (node2 !== null) {
+            node2.hidden = (errorString.indexOf('Invalid response') < 0);
+        }
     } else {
-        node.hidden = true;
-        node.textContent = '';
+        if (node !== null) {
+            node.hidden = true;
+            node.textContent = '';
+        }
+
+        if (node2 !== null) {
+            node2.hidden = true;
+        }
     }
 }
 
diff --git a/ext/bg/js/settings/audio-ui.js b/ext/bg/js/settings/audio-ui.js
index 711c2291..555380b4 100644
--- a/ext/bg/js/settings/audio-ui.js
+++ b/ext/bg/js/settings/audio-ui.js
@@ -16,7 +16,6 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-
 class AudioSourceUI {
     static instantiateTemplate(templateSelector) {
         const template = document.querySelector(templateSelector);
diff --git a/ext/bg/js/settings/audio.js b/ext/bg/js/settings/audio.js
index cff3f521..588d9a11 100644
--- a/ext/bg/js/settings/audio.js
+++ b/ext/bg/js/settings/audio.js
@@ -16,6 +16,8 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, settingsSaveOptions
+AudioSourceUI, audioGetTextToSpeechVoice*/
 
 let audioSourceUI = null;
 
diff --git a/ext/bg/js/settings/backup.js b/ext/bg/js/settings/backup.js
index becdc568..f4d622a4 100644
--- a/ext/bg/js/settings/backup.js
+++ b/ext/bg/js/settings/backup.js
@@ -16,6 +16,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGetFull, apiGetEnvironmentInfo
+utilBackend, utilIsolate, utilBackgroundIsolate, utilReadFileArrayBuffer
+optionsGetDefault, optionsUpdateVersion
+profileOptionsGetDefaultFieldTemplates*/
 
 // Exporting
 
@@ -159,7 +163,6 @@ async function _showSettingsImportWarnings(warnings) {
                 sanitize: e.currentTarget.dataset.importSanitize === 'true'
             });
             modalNode.modal('hide');
-
         };
         const onModalHide = () => {
             complete({result: false});
diff --git a/ext/bg/js/settings/conditions-ui.js b/ext/bg/js/settings/conditions-ui.js
index 4d041451..5a271321 100644
--- a/ext/bg/js/settings/conditions-ui.js
+++ b/ext/bg/js/settings/conditions-ui.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global conditionsNormalizeOptionValue*/
 
 class ConditionsUI {
     static instantiateTemplate(templateSelector) {
diff --git a/ext/bg/js/settings/dictionaries.js b/ext/bg/js/settings/dictionaries.js
index ed171ae9..70a22a16 100644
--- a/ext/bg/js/settings/dictionaries.js
+++ b/ext/bg/js/settings/dictionaries.js
@@ -16,6 +16,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, getOptionsMutable, getOptionsFullMutable, settingsSaveOptions, apiOptionsGetFull, apiOptionsGet
+utilBackgroundIsolate, utilDatabaseDeleteDictionary, utilDatabaseGetDictionaryInfo, utilDatabaseGetDictionaryCounts
+utilDatabasePurge, utilDatabaseImport
+storageUpdateStats, storageEstimate
+PageExitPrevention*/
 
 let dictionaryUI = null;
 
@@ -161,7 +166,7 @@ class SettingsDictionaryListUI {
         delete n.dataset.dict;
         $(n).modal('hide');
 
-        const index = this.dictionaryEntries.findIndex((e) => e.dictionaryInfo.title === title);
+        const index = this.dictionaryEntries.findIndex((entry) => entry.dictionaryInfo.title === title);
         if (index >= 0) {
             this.dictionaryEntries[index].deleteDictionary();
         }
@@ -174,7 +179,7 @@ class SettingsDictionaryEntryUI {
         this.dictionaryInfo = dictionaryInfo;
         this.optionsDictionary = optionsDictionary;
         this.counts = null;
-        this.eventListeners = [];
+        this.eventListeners = new EventListenerCollection();
         this.isDeleting = false;
 
         this.content = content;
@@ -193,10 +198,10 @@ class SettingsDictionaryEntryUI {
 
         this.applyValues();
 
-        this.addEventListener(this.enabledCheckbox, 'change', (e) => this.onEnabledChanged(e), false);
-        this.addEventListener(this.allowSecondarySearchesCheckbox, 'change', (e) => this.onAllowSecondarySearchesChanged(e), false);
-        this.addEventListener(this.priorityInput, 'change', (e) => this.onPriorityChanged(e), false);
-        this.addEventListener(this.deleteButton, 'click', (e) => this.onDeleteButtonClicked(e), false);
+        this.eventListeners.addEventListener(this.enabledCheckbox, 'change', (e) => this.onEnabledChanged(e), false);
+        this.eventListeners.addEventListener(this.allowSecondarySearchesCheckbox, 'change', (e) => this.onAllowSecondarySearchesChanged(e), false);
+        this.eventListeners.addEventListener(this.priorityInput, 'change', (e) => this.onPriorityChanged(e), false);
+        this.eventListeners.addEventListener(this.deleteButton, 'click', (e) => this.onDeleteButtonClicked(e), false);
     }
 
     cleanup() {
@@ -207,7 +212,7 @@ class SettingsDictionaryEntryUI {
             this.content = null;
         }
         this.dictionaryInfo = null;
-        this.clearEventListeners();
+        this.eventListeners.removeAllEventListeners();
     }
 
     setCounts(counts) {
@@ -224,18 +229,6 @@ class SettingsDictionaryEntryUI {
         this.parent.save();
     }
 
-    addEventListener(node, type, listener, options) {
-        node.addEventListener(type, listener, options);
-        this.eventListeners.push([node, type, listener, options]);
-    }
-
-    clearEventListeners() {
-        for (const [node, type, listener, options] of this.eventListeners) {
-            node.removeEventListener(type, listener, options);
-        }
-        this.eventListeners = [];
-    }
-
     applyValues() {
         this.enabledCheckbox.checked = this.optionsDictionary.enabled;
         this.allowSecondarySearchesCheckbox.checked = this.optionsDictionary.allowSecondarySearches;
@@ -272,9 +265,7 @@ class SettingsDictionaryEntryUI {
             this.isDeleting = false;
             progress.hidden = true;
 
-            const optionsContext = getOptionsContext();
-            const options = await getOptionsMutable(optionsContext);
-            onDatabaseUpdated(options);
+            onDatabaseUpdated();
         }
     }
 
@@ -359,28 +350,33 @@ async function dictSettingsInitialize() {
     document.querySelector('#dict-main').addEventListener('change', (e) => onDictionaryMainChanged(e), false);
     document.querySelector('#database-enable-prefix-wildcard-searches').addEventListener('change', (e) => onDatabaseEnablePrefixWildcardSearchesChanged(e), false);
 
-    const optionsContext = getOptionsContext();
-    const options = await getOptionsMutable(optionsContext);
-    onDictionaryOptionsChanged(options);
-    onDatabaseUpdated(options);
+    await onDictionaryOptionsChanged();
+    await onDatabaseUpdated();
 }
 
-async function onDictionaryOptionsChanged(options) {
+async function onDictionaryOptionsChanged() {
     if (dictionaryUI === null) { return; }
+
+    const optionsContext = getOptionsContext();
+    const options = await getOptionsMutable(optionsContext);
+
     dictionaryUI.setOptionsDictionaries(options.dictionaries);
 
     const optionsFull = await apiOptionsGetFull();
     document.querySelector('#database-enable-prefix-wildcard-searches').checked = optionsFull.global.database.prefixWildcardsSupported;
+
+    await updateMainDictionarySelectValue();
 }
 
-async function onDatabaseUpdated(options) {
+async function onDatabaseUpdated() {
     try {
         const dictionaries = await utilDatabaseGetDictionaryInfo();
         dictionaryUI.setDictionaries(dictionaries);
 
         document.querySelector('#dict-warning').hidden = (dictionaries.length > 0);
 
-        updateMainDictionarySelect(options, dictionaries);
+        updateMainDictionarySelectOptions(dictionaries);
+        await updateMainDictionarySelectValue();
 
         const {counts, total} = await utilDatabaseGetDictionaryCounts(dictionaries.map((v) => v.title), true);
         dictionaryUI.setCounts(counts, total);
@@ -389,7 +385,7 @@ async function onDatabaseUpdated(options) {
     }
 }
 
-async function updateMainDictionarySelect(options, dictionaries) {
+function updateMainDictionarySelectOptions(dictionaries) {
     const select = document.querySelector('#dict-main');
     select.textContent = ''; // Empty
 
@@ -399,8 +395,6 @@ async function updateMainDictionarySelect(options, dictionaries) {
     option.textContent = 'Not selected';
     select.appendChild(option);
 
-    let value = '';
-    const currentValue = options.general.mainDictionary;
     for (const {title, sequenced} of toIterable(dictionaries)) {
         if (!sequenced) { continue; }
 
@@ -408,26 +402,56 @@ async function updateMainDictionarySelect(options, dictionaries) {
         option.value = title;
         option.textContent = title;
         select.appendChild(option);
+    }
+}
+
+async function updateMainDictionarySelectValue() {
+    const optionsContext = getOptionsContext();
+    const options = await apiOptionsGet(optionsContext);
 
-        if (title === currentValue) {
-            value = title;
+    const value = options.general.mainDictionary;
+
+    const select = document.querySelector('#dict-main');
+    let selectValue = null;
+    for (const child of select.children) {
+        if (child.nodeName.toUpperCase() === 'OPTION' && child.value === value) {
+            selectValue = value;
+            break;
         }
     }
 
-    select.value = value;
-
-    if (options.general.mainDictionary !== value) {
-        options.general.mainDictionary = value;
-        settingsSaveOptions();
+    let missingNodeOption = select.querySelector('option[data-not-installed=true]');
+    if (selectValue === null) {
+        if (missingNodeOption === null) {
+            missingNodeOption = document.createElement('option');
+            missingNodeOption.className = 'text-muted';
+            missingNodeOption.value = value;
+            missingNodeOption.textContent = `${value} (Not installed)`;
+            missingNodeOption.dataset.notInstalled = 'true';
+            select.appendChild(missingNodeOption);
+        }
+    } else {
+        if (missingNodeOption !== null) {
+            missingNodeOption.parentNode.removeChild(missingNodeOption);
+        }
     }
+
+    select.value = value;
 }
 
 async function onDictionaryMainChanged(e) {
-    const value = e.target.value;
+    const select = e.target;
+    const value = select.value;
+
+    const missingNodeOption = select.querySelector('option[data-not-installed=true]');
+    if (missingNodeOption !== null && missingNodeOption.value !== value) {
+        missingNodeOption.parentNode.removeChild(missingNodeOption);
+    }
+
     const optionsContext = getOptionsContext();
     const options = await getOptionsMutable(optionsContext);
     options.general.mainDictionary = value;
-    settingsSaveOptions();
+    await settingsSaveOptions();
 }
 
 
@@ -467,15 +491,18 @@ function dictionaryErrorsShow(errors) {
     dialog.textContent = '';
 
     if (errors !== null && errors.length > 0) {
-        const uniqueErrors = {};
+        const uniqueErrors = new Map();
         for (let e of errors) {
             console.error(e);
             e = dictionaryErrorToString(e);
-            uniqueErrors[e] = hasOwn(uniqueErrors, e) ? uniqueErrors[e] + 1 : 1;
+            let count = uniqueErrors.get(e);
+            if (typeof count === 'undefined') {
+                count = 0;
+            }
+            uniqueErrors.set(e, count + 1);
         }
 
-        for (const e in uniqueErrors) {
-            const count = uniqueErrors[e];
+        for (const [e, count] of uniqueErrors.entries()) {
             const div = document.createElement('p');
             if (count > 1) {
                 div.textContent = `${e} `;
@@ -537,9 +564,7 @@ async function onDictionaryPurge(e) {
         }
         await settingsSaveOptions();
 
-        const optionsContext = getOptionsContext();
-        const options = await getOptionsMutable(optionsContext);
-        onDatabaseUpdated(options);
+        onDatabaseUpdated();
     } catch (err) {
         dictionaryErrorsShow([err]);
     } finally {
@@ -611,9 +636,7 @@ async function onDictionaryImport(e) {
                 dictionaryErrorsShow(errors);
             }
 
-            const optionsContext = getOptionsContext();
-            const options = await getOptionsMutable(optionsContext);
-            onDatabaseUpdated(options);
+            onDatabaseUpdated();
         }
     } catch (err) {
         dictionaryErrorsShow([err]);
diff --git a/ext/bg/js/settings/main.js b/ext/bg/js/settings/main.js
index 3bf65eda..d1ad2c6b 100644
--- a/ext/bg/js/settings/main.js
+++ b/ext/bg/js/settings/main.js
@@ -16,6 +16,14 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsContext, apiOptionsSave
+utilBackend, utilIsolate, utilBackgroundIsolate
+ankiErrorShown, ankiFieldsToDict
+ankiTemplatesUpdateValue, onAnkiOptionsChanged, onDictionaryOptionsChanged
+appearanceInitialize, audioSettingsInitialize, profileOptionsSetup, dictSettingsInitialize
+ankiInitialize, ankiTemplatesInitialize, storageInfoInitialize
+*/
+
 function getOptionsMutable(optionsContext) {
     return utilBackend().getOptions(
         utilBackgroundIsolate(optionsContext)
@@ -28,6 +36,22 @@ function getOptionsFullMutable() {
 
 async function formRead(options) {
     options.general.enable = $('#enable').prop('checked');
+    const enableClipboardPopups = $('#enable-clipboard-popups').prop('checked');
+    if (enableClipboardPopups) {
+        options.general.enableClipboardPopups = await new Promise((resolve, _reject) => {
+            chrome.permissions.request(
+                {permissions: ['clipboardRead']},
+                (granted) => {
+                    if (!granted) {
+                        $('#enable-clipboard-popups').prop('checked', false);
+                    }
+                    resolve(granted);
+                }
+            );
+        });
+    } else {
+        options.general.enableClipboardPopups = false;
+    }
     options.general.showGuide = $('#show-usage-guide').prop('checked');
     options.general.compactTags = $('#compact-tags').prop('checked');
     options.general.compactGlossaries = $('#compact-glossaries').prop('checked');
@@ -44,7 +68,7 @@ async function formRead(options) {
     options.general.popupVerticalOffset = parseInt($('#popup-vertical-offset').val(), 10);
     options.general.popupHorizontalOffset2 = parseInt($('#popup-horizontal-offset2').val(), 0);
     options.general.popupVerticalOffset2 = parseInt($('#popup-vertical-offset2').val(), 10);
-    options.general.popupScalingFactor = parseInt($('#popup-scaling-factor').val(), 10);
+    options.general.popupScalingFactor = parseFloat($('#popup-scaling-factor').val());
     options.general.popupScaleRelativeToPageZoom = $('#popup-scale-relative-to-page-zoom').prop('checked');
     options.general.popupScaleRelativeToVisualViewport = $('#popup-scale-relative-to-visual-viewport').prop('checked');
     options.general.popupTheme = $('#popup-theme').val();
@@ -67,6 +91,7 @@ async function formRead(options) {
     options.scanning.enablePopupSearch = $('#enable-search-within-first-popup').prop('checked');
     options.scanning.enableOnPopupExpressions = $('#enable-scanning-of-popup-expressions').prop('checked');
     options.scanning.enableOnSearchPage = $('#enable-scanning-on-search-page').prop('checked');
+    options.scanning.enableSearchTags = $('#enable-search-tags').prop('checked');
     options.scanning.delay = parseInt($('#scan-delay').val(), 10);
     options.scanning.length = parseInt($('#scan-length').val(), 10);
     options.scanning.modifier = $('#scan-modifier-key').val();
@@ -103,6 +128,7 @@ async function formRead(options) {
 
 async function formWrite(options) {
     $('#enable').prop('checked', options.general.enable);
+    $('#enable-clipboard-popups').prop('checked', options.general.enableClipboardPopups);
     $('#show-usage-guide').prop('checked', options.general.showGuide);
     $('#compact-tags').prop('checked', options.general.compactTags);
     $('#compact-glossaries').prop('checked', options.general.compactGlossaries);
@@ -142,6 +168,7 @@ async function formWrite(options) {
     $('#enable-search-within-first-popup').prop('checked', options.scanning.enablePopupSearch);
     $('#enable-scanning-of-popup-expressions').prop('checked', options.scanning.enableOnPopupExpressions);
     $('#enable-scanning-on-search-page').prop('checked', options.scanning.enableOnSearchPage);
+    $('#enable-search-tags').prop('checked', options.scanning.enableSearchTags);
     $('#scan-delay').val(options.scanning.delay);
     $('#scan-length').val(options.scanning.length);
     $('#scan-modifier-key').val(options.scanning.modifier);
@@ -167,7 +194,7 @@ async function formWrite(options) {
 
     await ankiTemplatesUpdateValue();
     await onAnkiOptionsChanged(options);
-    await onDictionaryOptionsChanged(options);
+    await onDictionaryOptionsChanged();
 
     formUpdateVisibility(options);
 }
@@ -215,7 +242,7 @@ async function settingsSaveOptions() {
     await apiOptionsSave(source);
 }
 
-async function onOptionsUpdate({source}) {
+async function onOptionsUpdated({source}) {
     const thisSource = await settingsGetSource();
     if (source === thisSource) { return; }
 
@@ -247,7 +274,7 @@ async function onReady() {
 
     storageInfoInitialize();
 
-    yomichan.on('optionsUpdate', onOptionsUpdate);
+    yomichan.on('optionsUpdated', onOptionsUpdated);
 }
 
 $(document).ready(() => onReady());
diff --git a/ext/bg/js/settings/popup-preview-frame.js b/ext/bg/js/settings/popup-preview-frame.js
index 37a4b416..aa2b6100 100644
--- a/ext/bg/js/settings/popup-preview-frame.js
+++ b/ext/bg/js/settings/popup-preview-frame.js
@@ -16,15 +16,18 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiOptionsGet, Popup, PopupProxyHost, Frontend, TextSourceRange*/
 
 class SettingsPopupPreview {
     constructor() {
         this.frontend = null;
         this.apiOptionsGetOld = apiOptionsGet;
-        this.popupInjectOuterStylesheetOld = Popup.injectOuterStylesheet;
+        this.popup = null;
+        this.popupSetCustomOuterCssOld = null;
         this.popupShown = false;
         this.themeChangeTimeout = null;
         this.textSource = null;
+        this._targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');
     }
 
     static create() {
@@ -49,18 +52,18 @@ class SettingsPopupPreview {
         const popupHost = new PopupProxyHost();
         await popupHost.prepare();
 
-        const popup = popupHost.createPopup(null, 0);
-        popup.setChildrenSupported(false);
+        this.popup = popupHost.getOrCreatePopup();
+        this.popup.setChildrenSupported(false);
 
-        this.frontend = new Frontend(popup);
+        this.popupSetCustomOuterCssOld = this.popup.setCustomOuterCss;
+        this.popup.setCustomOuterCss = (...args) => this.popupSetCustomOuterCss(...args);
 
-        this.frontend.setEnabled = function () {};
-        this.frontend.searchClear = function () {};
+        this.frontend = new Frontend(this.popup);
 
-        await this.frontend.prepare();
+        this.frontend.setEnabled = () => {};
+        this.frontend.searchClear = () => {};
 
-        // Overwrite popup
-        Popup.injectOuterStylesheet = (...args) => this.popupInjectOuterStylesheet(...args);
+        await this.frontend.prepare();
 
         // Update search
         this.updateSearch();
@@ -82,20 +85,21 @@ class SettingsPopupPreview {
         return options;
     }
 
-    popupInjectOuterStylesheet(...args) {
+    async popupSetCustomOuterCss(...args) {
         // This simulates the stylesheet priorities when injecting using the web extension API.
-        const result = this.popupInjectOuterStylesheetOld(...args);
+        const result = await this.popupSetCustomOuterCssOld.call(this.popup, ...args);
 
-        const outerStylesheet = Popup.outerStylesheet;
         const node = document.querySelector('#client-css');
-        if (node !== null && outerStylesheet !== null) {
-            node.parentNode.insertBefore(outerStylesheet, node);
+        if (node !== null && result !== null) {
+            node.parentNode.insertBefore(result, node);
         }
 
         return result;
     }
 
     onMessage(e) {
+        if (e.origin !== this._targetOrigin) { return; }
+
         const {action, params} = e.data;
         const handler = SettingsPopupPreview._messageHandlers.get(action);
         if (typeof handler !== 'function') { return; }
@@ -136,7 +140,7 @@ class SettingsPopupPreview {
 
     setCustomOuterCss(css) {
         if (this.frontend === null) { return; }
-        this.frontend.popup.setCustomOuterCss(css, true);
+        this.frontend.popup.setCustomOuterCss(css, false);
     }
 
     async updateSearch() {
diff --git a/ext/bg/js/settings/popup-preview.js b/ext/bg/js/settings/popup-preview.js
index 0d20471e..d1d2ff5e 100644
--- a/ext/bg/js/settings/popup-preview.js
+++ b/ext/bg/js/settings/popup-preview.js
@@ -40,20 +40,22 @@ function showAppearancePreview() {
 
     window.wanakana.bind(text[0]);
 
+    const targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');
+
     text.on('input', () => {
         const action = 'setText';
         const params = {text: text.val()};
-        frame.contentWindow.postMessage({action, params}, '*');
+        frame.contentWindow.postMessage({action, params}, targetOrigin);
     });
     customCss.on('input', () => {
         const action = 'setCustomCss';
         const params = {css: customCss.val()};
-        frame.contentWindow.postMessage({action, params}, '*');
+        frame.contentWindow.postMessage({action, params}, targetOrigin);
     });
     customOuterCss.on('input', () => {
         const action = 'setCustomOuterCss';
         const params = {css: customOuterCss.val()};
-        frame.contentWindow.postMessage({action, params}, '*');
+        frame.contentWindow.postMessage({action, params}, targetOrigin);
     });
 
     container.append(frame);
diff --git a/ext/bg/js/settings/profiles.js b/ext/bg/js/settings/profiles.js
index c4e68b53..3e589809 100644
--- a/ext/bg/js/settings/profiles.js
+++ b/ext/bg/js/settings/profiles.js
@@ -16,6 +16,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global getOptionsMutable, getOptionsFullMutable, settingsSaveOptions, apiOptionsGetFull
+utilBackgroundIsolate, formWrite
+conditionsClearCaches, ConditionsUI, profileConditionsDescriptor*/
+
 let currentProfileIndex = 0;
 let profileConditionsContainer = null;
 
diff --git a/ext/bg/js/settings/storage.js b/ext/bg/js/settings/storage.js
index 6c10f665..cbe1bb4d 100644
--- a/ext/bg/js/settings/storage.js
+++ b/ext/bg/js/settings/storage.js
@@ -16,6 +16,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global apiGetEnvironmentInfo*/
 
 function storageBytesToLabeledString(size) {
     const base = 1000;
diff --git a/ext/bg/js/templates.js b/ext/bg/js/templates.js
deleted file mode 100644
index 2f65be31..00000000
--- a/ext/bg/js/templates.js
+++ /dev/null
@@ -1,55 +0,0 @@
-(function() {
-  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-templates['query-parser.html'] = template({"1":function(container,depth0,helpers,partials,data) {
-    var stack1, alias1=depth0 != null ? depth0 : (container.nullContext || {});
-
-  return ((stack1 = helpers["if"].call(alias1,(depth0 != null ? depth0.preview : depth0),{"name":"if","hash":{},"fn":container.program(2, data, 0),"inverse":container.program(4, data, 0),"data":data})) != null ? stack1 : "")
-    + ((stack1 = helpers.each.call(alias1,depth0,{"name":"each","hash":{},"fn":container.program(6, data, 0),"inverse":container.noop,"data":data})) != null ? stack1 : "")
-    + "</span>";
-},"2":function(container,depth0,helpers,partials,data) {
-    return "<span class=\"query-parser-term-preview\">";
-},"4":function(container,depth0,helpers,partials,data) {
-    return "<span class=\"query-parser-term\">";
-},"6":function(container,depth0,helpers,partials,data) {
-    var stack1;
-
-  return ((stack1 = container.invokePartial(partials.part,depth0,{"name":"part","data":data,"helpers":helpers,"partials":partials,"decorators":container.decorators})) != null ? stack1 : "");
-},"8":function(container,depth0,helpers,partials,data) {
-    var stack1;
-
-  return ((stack1 = helpers["if"].call(depth0 != null ? depth0 : (container.nullContext || {}),(depth0 != null ? depth0.raw : depth0),{"name":"if","hash":{},"fn":container.program(9, data, 0),"inverse":container.program(12, data, 0),"data":data})) != null ? stack1 : "");
-},"9":function(container,depth0,helpers,partials,data) {
-    var stack1;
-
-  return ((stack1 = helpers.each.call(depth0 != null ? depth0 : (container.nullContext || {}),(depth0 != null ? depth0.text : depth0),{"name":"each","hash":{},"fn":container.program(10, data, 0),"inverse":container.noop,"data":data})) != null ? stack1 : "");
-},"10":function(container,depth0,helpers,partials,data) {
-    return "<span class=\"query-parser-char\">"
-    + container.escapeExpression(container.lambda(depth0, depth0))
-    + "</span>";
-},"12":function(container,depth0,helpers,partials,data) {
-    var stack1, helper, alias1=depth0 != null ? depth0 : (container.nullContext || {});
-
-  return "<ruby>"
-    + ((stack1 = helpers.each.call(alias1,(depth0 != null ? depth0.text : depth0),{"name":"each","hash":{},"fn":container.program(10, data, 0),"inverse":container.noop,"data":data})) != null ? stack1 : "")
-    + "<rt>"
-    + container.escapeExpression(((helper = (helper = helpers.reading || (depth0 != null ? depth0.reading : depth0)) != null ? helper : helpers.helperMissing),(typeof helper === "function" ? helper.call(alias1,{"name":"reading","hash":{},"data":data}) : helper)))
-    + "</rt></ruby>";
-},"14":function(container,depth0,helpers,partials,data,blockParams,depths) {
-    var stack1;
-
-  return ((stack1 = container.invokePartial(partials.term,depth0,{"name":"term","hash":{"preview":(depths[1] != null ? depths[1].preview : depths[1])},"data":data,"helpers":helpers,"partials":partials,"decorators":container.decorators})) != null ? stack1 : "");
-},"compiler":[7,">= 4.0.0"],"main":function(container,depth0,helpers,partials,data,blockParams,depths) {
-    var stack1;
-
-  return ((stack1 = helpers.each.call(depth0 != null ? depth0 : (container.nullContext || {}),(depth0 != null ? depth0.terms : depth0),{"name":"each","hash":{},"fn":container.program(14, data, 0, blockParams, depths),"inverse":container.noop,"data":data})) != null ? stack1 : "");
-},"main_d":  function(fn, props, container, depth0, data, blockParams, depths) {
-
-  var decorators = container.decorators;
-
-  fn = decorators.inline(fn,props,container,{"name":"inline","hash":{},"fn":container.program(1, data, 0, blockParams, depths),"inverse":container.noop,"args":["term"],"data":data}) || fn;
-  fn = decorators.inline(fn,props,container,{"name":"inline","hash":{},"fn":container.program(8, data, 0, blockParams, depths),"inverse":container.noop,"args":["part"],"data":data}) || fn;
-  return fn;
-  }
-
-,"useDecorators":true,"usePartial":true,"useData":true,"useDepths":true});
-})();
\ No newline at end of file
diff --git a/ext/bg/js/translator.js b/ext/bg/js/translator.js
index dfec54ac..a675a9f7 100644
--- a/ext/bg/js/translator.js
+++ b/ext/bg/js/translator.js
@@ -16,12 +16,18 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/*global requestJson
+dictTermsMergeBySequence, dictTagBuildSource, dictTermsMergeByGloss, dictTermsSort, dictTagsSort
+dictEnabledSet, dictTermsGroup, dictTermsCompressTags, dictTermsUndupe, dictTagSanitize
+jpDistributeFurigana, jpConvertHalfWidthKanaToFullWidth, jpConvertNumericTofullWidth
+jpConvertAlphabeticToKana, jpHiraganaToKatakana, jpKatakanaToHiragana, jpIsCharCodeJapanese
+Database, Deinflector*/
 
 class Translator {
     constructor() {
         this.database = null;
         this.deinflector = null;
-        this.tagCache = {};
+        this.tagCache = new Map();
     }
 
     async prepare() {
@@ -38,24 +44,24 @@ class Translator {
     }
 
     async purgeDatabase() {
-        this.tagCache = {};
+        this.tagCache.clear();
         await this.database.purge();
     }
 
     async deleteDictionary(dictionaryName) {
-        this.tagCache = {};
+        this.tagCache.clear();
         await this.database.deleteDictionary(dictionaryName);
     }
 
     async getSequencedDefinitions(definitions, mainDictionary) {
-        const definitionsBySequence = dictTermsMergeBySequence(definitions, mainDictionary);
-        const defaultDefinitions = definitionsBySequence['-1'];
+        const [definitionsBySequence, defaultDefinitions] = dictTermsMergeBySequence(definitions, mainDictionary);
 
-        const sequenceList = Object.keys(definitionsBySequence).map((v) => Number(v)).filter((v) => v >= 0);
-        const sequencedDefinitions = sequenceList.map((key) => ({
-            definitions: definitionsBySequence[key],
-            rawDefinitions: []
-        }));
+        const sequenceList = [];
+        const sequencedDefinitions = [];
+        for (const [key, value] of definitionsBySequence.entries()) {
+            sequenceList.push(key);
+            sequencedDefinitions.push({definitions: value, rawDefinitions: []});
+        }
 
         for (const definition of await this.database.findTermsBySequenceBulk(sequenceList, mainDictionary)) {
             sequencedDefinitions[definition.index].rawDefinitions.push(definition);
@@ -64,8 +70,8 @@ class Translator {
         return {sequencedDefinitions, defaultDefinitions};
     }
 
-    async getMergedSecondarySearchResults(text, expressionsMap, secondarySearchTitles) {
-        if (secondarySearchTitles.length === 0) {
+    async getMergedSecondarySearchResults(text, expressionsMap, secondarySearchDictionaries) {
+        if (secondarySearchDictionaries.size === 0) {
             return [];
         }
 
@@ -79,7 +85,7 @@ class Translator {
             }
         }
 
-        const definitions = await this.database.findTermsExactBulk(expressionList, readingList, secondarySearchTitles);
+        const definitions = await this.database.findTermsExactBulk(expressionList, readingList, secondarySearchDictionaries);
         for (const definition of definitions) {
             const definitionTags = await this.expandTags(definition.definitionTags, definition.dictionary);
             definitionTags.push(dictTagBuildSource(definition.dictionary));
@@ -95,7 +101,7 @@ class Translator {
         return definitions;
     }
 
-    async getMergedDefinition(text, dictionaries, sequencedDefinition, defaultDefinitions, secondarySearchTitles, mergedByTermIndices) {
+    async getMergedDefinition(text, dictionaries, sequencedDefinition, defaultDefinitions, secondarySearchDictionaries, mergedByTermIndices) {
         const result = sequencedDefinition.definitions;
         const rawDefinitionsBySequence = sequencedDefinition.rawDefinitions;
 
@@ -108,12 +114,11 @@ class Translator {
         }
 
         const definitionsByGloss = dictTermsMergeByGloss(result, rawDefinitionsBySequence);
-        const secondarySearchResults = await this.getMergedSecondarySearchResults(text, result.expressions, secondarySearchTitles);
+        const secondarySearchResults = await this.getMergedSecondarySearchResults(text, result.expressions, secondarySearchDictionaries);
 
         dictTermsMergeByGloss(result, defaultDefinitions.concat(secondarySearchResults), definitionsByGloss, mergedByTermIndices);
 
-        for (const gloss in definitionsByGloss) {
-            const definition = definitionsByGloss[gloss];
+        for (const definition of definitionsByGloss.values()) {
             dictTagsSort(definition.definitionTags);
             result.definitions.push(definition);
         }
@@ -122,7 +127,8 @@ class Translator {
 
         const expressions = [];
         for (const [expression, readingMap] of result.expressions.entries()) {
-            for (const [reading, termTags] of readingMap.entries()) {
+            for (const [reading, termTagsMap] of readingMap.entries()) {
+                const termTags = [...termTagsMap.values()];
                 const score = termTags.map((tag) => tag.score).reduce((p, v) => p + v, 0);
                 expressions.push(Translator.createExpression(expression, reading, dictTagsSort(termTags), Translator.scoreToTermFrequency(score)));
             }
@@ -135,14 +141,16 @@ class Translator {
         return result;
     }
 
-    async findTerms(text, details, options) {
-        switch (options.general.resultOutputMode) {
+    async findTerms(mode, text, details, options) {
+        switch (mode) {
             case 'group':
                 return await this.findTermsGrouped(text, details, options);
             case 'merge':
                 return await this.findTermsMerged(text, details, options);
             case 'split':
                 return await this.findTermsSplit(text, details, options);
+            case 'simple':
+                return await this.findTermsSimple(text, details, options);
             default:
                 return [[], 0];
         }
@@ -150,11 +158,10 @@ class Translator {
 
     async findTermsGrouped(text, details, options) {
         const dictionaries = dictEnabledSet(options);
-        const titles = Object.keys(dictionaries);
         const [definitions, length] = await this.findTermsInternal(text, dictionaries, details, options);
 
         const definitionsGrouped = dictTermsGroup(definitions, dictionaries);
-        await this.buildTermMeta(definitionsGrouped, titles);
+        await this.buildTermMeta(definitionsGrouped, dictionaries);
 
         if (options.general.compactTags) {
             for (const definition of definitionsGrouped) {
@@ -167,8 +174,12 @@ class Translator {
 
     async findTermsMerged(text, details, options) {
         const dictionaries = dictEnabledSet(options);
-        const secondarySearchTitles = Object.keys(options.dictionaries).filter((dict) => options.dictionaries[dict].allowSecondarySearches);
-        const titles = Object.keys(dictionaries);
+        const secondarySearchDictionaries = new Map();
+        for (const [title, dictionary] of dictionaries.entries()) {
+            if (!dictionary.allowSecondarySearches) { continue; }
+            secondarySearchDictionaries.set(title, dictionary);
+        }
+
         const [definitions, length] = await this.findTermsInternal(text, dictionaries, details, options);
         const {sequencedDefinitions, defaultDefinitions} = await this.getSequencedDefinitions(definitions, options.general.mainDictionary);
         const definitionsMerged = [];
@@ -180,7 +191,7 @@ class Translator {
                 dictionaries,
                 sequencedDefinition,
                 defaultDefinitions,
-                secondarySearchTitles,
+                secondarySearchDictionaries,
                 mergedByTermIndices
             );
             definitionsMerged.push(result);
@@ -192,7 +203,7 @@ class Translator {
             definitionsMerged.push(groupedDefinition);
         }
 
-        await this.buildTermMeta(definitionsMerged, titles);
+        await this.buildTermMeta(definitionsMerged, dictionaries);
 
         if (options.general.compactTags) {
             for (const definition of definitionsMerged) {
@@ -205,25 +216,28 @@ class Translator {
 
     async findTermsSplit(text, details, options) {
         const dictionaries = dictEnabledSet(options);
-        const titles = Object.keys(dictionaries);
         const [definitions, length] = await this.findTermsInternal(text, dictionaries, details, options);
 
-        await this.buildTermMeta(definitions, titles);
+        await this.buildTermMeta(definitions, dictionaries);
 
         return [definitions, length];
     }
 
+    async findTermsSimple(text, details, options) {
+        const dictionaries = dictEnabledSet(options);
+        return await this.findTermsInternal(text, dictionaries, details, options);
+    }
+
     async findTermsInternal(text, dictionaries, details, options) {
         text = Translator.getSearchableText(text, options);
         if (text.length === 0) {
             return [[], 0];
         }
 
-        const titles = Object.keys(dictionaries);
         const deinflections = (
             details.wildcard ?
-            await this.findTermWildcard(text, titles, details.wildcard) :
-            await this.findTermDeinflections(text, titles, options)
+            await this.findTermWildcard(text, dictionaries, details.wildcard) :
+            await this.findTermDeinflections(text, dictionaries, options)
         );
 
         let definitions = [];
@@ -265,8 +279,8 @@ class Translator {
         return [definitions, length];
     }
 
-    async findTermWildcard(text, titles, wildcard) {
-        const definitions = await this.database.findTermsBulk([text], titles, wildcard);
+    async findTermWildcard(text, dictionaries, wildcard) {
+        const definitions = await this.database.findTermsBulk([text], dictionaries, wildcard);
         if (definitions.length === 0) {
             return [];
         }
@@ -281,7 +295,7 @@ class Translator {
         }];
     }
 
-    async findTermDeinflections(text, titles, options) {
+    async findTermDeinflections(text, dictionaries, options) {
         const deinflections = this.getAllDeinflections(text, options);
 
         if (deinflections.length === 0) {
@@ -303,7 +317,7 @@ class Translator {
             deinflectionArray.push(deinflection);
         }
 
-        const definitions = await this.database.findTermsBulk(uniqueDeinflectionTerms, titles, null);
+        const definitions = await this.database.findTermsBulk(uniqueDeinflectionTerms, dictionaries, null);
 
         for (const definition of definitions) {
             const definitionRules = Deinflector.rulesToRuleFlags(definition.rules);
@@ -393,17 +407,12 @@ class Translator {
 
     async findKanji(text, options) {
         const dictionaries = dictEnabledSet(options);
-        const titles = Object.keys(dictionaries);
-        const kanjiUnique = {};
-        const kanjiList = [];
+        const kanjiUnique = new Set();
         for (const c of text) {
-            if (!hasOwn(kanjiUnique, c)) {
-                kanjiList.push(c);
-                kanjiUnique[c] = true;
-            }
+            kanjiUnique.add(c);
         }
 
-        const definitions = await this.database.findKanjiBulk(kanjiList, titles);
+        const definitions = await this.database.findKanjiBulk([...kanjiUnique], dictionaries);
         if (definitions.length === 0) {
             return definitions;
         }
@@ -423,12 +432,12 @@ class Translator {
             definition.stats = stats;
         }
 
-        await this.buildKanjiMeta(definitions, titles);
+        await this.buildKanjiMeta(definitions, dictionaries);
 
         return definitions;
     }
 
-    async buildTermMeta(definitions, titles) {
+    async buildTermMeta(definitions, dictionaries) {
         const terms = [];
         for (const definition of definitions) {
             if (definition.expressions) {
@@ -454,7 +463,7 @@ class Translator {
                 termList = [];
                 expressionsUnique.push(expression);
                 termsUnique.push(termList);
-                termsUniqueMap[expression] = termList;
+                termsUniqueMap.set(expression, termList);
             }
             termList.push(term);
 
@@ -462,7 +471,7 @@ class Translator {
             term.frequencies = [];
         }
 
-        const metas = await this.database.findTermMetaBulk(expressionsUnique, titles);
+        const metas = await this.database.findTermMetaBulk(expressionsUnique, dictionaries);
         for (const {expression, mode, data, dictionary, index} of metas) {
             switch (mode) {
                 case 'freq':
@@ -474,14 +483,14 @@ class Translator {
         }
     }
 
-    async buildKanjiMeta(definitions, titles) {
+    async buildKanjiMeta(definitions, dictionaries) {
         const kanjiList = [];
         for (const definition of definitions) {
             kanjiList.push(definition.character);
             definition.frequencies = [];
         }
 
-        const metas = await this.database.findKanjiMetaBulk(kanjiList, titles);
+        const metas = await this.database.findKanjiMetaBulk(kanjiList, dictionaries);
         for (const {character, mode, data, dictionary, index} of metas) {
             switch (mode) {
                 case 'freq':
@@ -504,49 +513,50 @@ class Translator {
         const names = Object.keys(items);
         const tagMetaList = await this.getTagMetaList(names, title);
 
-        const stats = {};
+        const statsGroups = new Map();
         for (let i = 0; i < names.length; ++i) {
             const name = names[i];
             const meta = tagMetaList[i];
             if (meta === null) { continue; }
 
             const category = meta.category;
-            const group = (
-                hasOwn(stats, category) ?
-                stats[category] :
-                (stats[category] = [])
-            );
+            let group = statsGroups.get(category);
+            if (typeof group === 'undefined') {
+                group = [];
+                statsGroups.set(category, group);
+            }
 
             const stat = Object.assign({}, meta, {name, value: items[name]});
             group.push(dictTagSanitize(stat));
         }
 
+        const stats = {};
         const sortCompare = (a, b) => a.notes - b.notes;
-        for (const category in stats) {
-            stats[category].sort(sortCompare);
+        for (const [category, group] of statsGroups.entries()) {
+            group.sort(sortCompare);
+            stats[category] = group;
         }
-
         return stats;
     }
 
     async getTagMetaList(names, title) {
         const tagMetaList = [];
-        const cache = (
-            hasOwn(this.tagCache, title) ?
-            this.tagCache[title] :
-            (this.tagCache[title] = {})
-        );
+        let cache = this.tagCache.get(title);
+        if (typeof cache === 'undefined') {
+            cache = new Map();
+            this.tagCache.set(title, cache);
+        }
 
         for (const name of names) {
             const base = Translator.getNameBase(name);
 
-            if (hasOwn(cache, base)) {
-                tagMetaList.push(cache[base]);
-            } else {
-                const tagMeta = await this.database.findTagForTitle(base, title);
-                cache[base] = tagMeta;
-                tagMetaList.push(tagMeta);
+            let tagMeta = cache.get(base);
+            if (typeof tagMeta === 'undefined') {
+                tagMeta = await this.database.findTagForTitle(base, title);
+                cache.set(base, tagMeta);
             }
+
+            tagMetaList.push(tagMeta);
         }
 
         return tagMetaList;
diff --git a/ext/bg/js/util.js b/ext/bg/js/util.js
index 333e814b..5ce4b08c 100644
--- a/ext/bg/js/util.js
+++ b/ext/bg/js/util.js
@@ -33,7 +33,7 @@ function utilIsolate(value) {
 }
 
 function utilFunctionIsolate(func) {
-    return function (...args) {
+    return function isolatedFunction(...args) {
         try {
             args = args.map((v) => utilIsolate(v));
             return func.call(this, ...args);
@@ -59,32 +59,6 @@ function utilBackgroundFunctionIsolate(func) {
     return backgroundPage.utilFunctionIsolate(func);
 }
 
-function utilSetEqual(setA, setB) {
-    if (setA.size !== setB.size) {
-        return false;
-    }
-
-    for (const value of setA) {
-        if (!setB.has(value)) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
-function utilSetIntersection(setA, setB) {
-    return new Set(
-        [...setA].filter((value) => setB.has(value))
-    );
-}
-
-function utilSetDifference(setA, setB) {
-    return new Set(
-        [...setA].filter((value) => !setB.has(value))
-    );
-}
-
 function utilStringHashCode(string) {
     let hashCode = 0;
 
diff --git a/ext/bg/query-parser-templates.html b/ext/bg/query-parser-templates.html
new file mode 100644
index 00000000..7cab16a9
--- /dev/null
+++ b/ext/bg/query-parser-templates.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html><html><head></head><body>
+
+<template id="term-template"><span class="query-parser-term" data-type="normal"></span></template>
+<template id="term-preview-template"><span class="query-parser-term" data-type="preview"></span></template>
+<template id="segment-template"><ruby class="query-parser-segment"><span class="query-parser-segment-text"></span><rt class="query-parser-segment-reading"></rt></ruby></template>
+<template id="char-template"><span class="query-parser-char"></span></template>
+
+<template id="select-template"><select class="query-parser-select form-control"></select></template>
+<template id="select-option-template"><option class="query-parser-select-option"></option></template>
+
+</body></html>
diff --git a/ext/bg/search.html b/ext/bg/search.html
index 74afbb68..d6336826 100644
--- a/ext/bg/search.html
+++ b/ext/bg/search.html
@@ -25,29 +25,31 @@
                 <p style="margin-bottom: 0;">Search your installed dictionaries by entering a Japanese expression into the field below.</p>
             </div>
 
-            <div class="input-group" style="padding-top: 20px;">
-                <span title="Enable kana input method" class="input-group-text">
-                    <input type="checkbox" id="wanakana-enable" class="icon-checkbox" />
-                    <label for="wanakana-enable" class="scan-disable">あ</label>
-                </span>
-                <span title="Enable clipboard monitor" class="input-group-text">
-                    <input type="checkbox" id="clipboard-monitor-enable" class="icon-checkbox" />
-                    <label for="clipboard-monitor-enable"><span class="glyphicon glyphicon-paste"></span></label>
-                </span>
-            </div>
+            <div class="search-input">
+                <div class="input-group" style="padding-top: 20px;">
+                    <span title="Enable kana input method" class="input-group-text">
+                        <input type="checkbox" id="wanakana-enable" class="icon-checkbox" />
+                        <label for="wanakana-enable" class="scan-disable">あ</label>
+                    </span>
+                    <span title="Enable clipboard monitor" class="input-group-text">
+                        <input type="checkbox" id="clipboard-monitor-enable" class="icon-checkbox" />
+                        <label for="clipboard-monitor-enable"><span class="glyphicon glyphicon-paste"></span></label>
+                    </span>
+                </div>
 
-            <form class="input-group">
-                <input type="text" class="form-control" placeholder="Search for..." id="query" autofocus>
-                <span class="input-group-btn">
-                    <input type="submit" class="btn btn-default form-control" id="search" value="Search">
-                </span>
-            </form>
+                <form class="input-group">
+                    <input type="text" class="form-control" placeholder="Search for..." id="query" autofocus>
+                    <span class="input-group-btn">
+                        <input type="submit" class="btn btn-default form-control" id="search" value="Search">
+                    </span>
+                </form>
+            </div>
 
             <div id="spinner" hidden><img src="/mixed/img/spinner.gif"></div>
 
             <div class="scan-disable">
-                <div id="query-parser-select" class="input-group"></div>
-                <div id="query-parser"></div>
+                <div id="query-parser-select-container" class="input-group"></div>
+                <div id="query-parser-content"></div>
             </div>
 
             <hr>
@@ -75,18 +77,20 @@
 
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
-        <script src="/bg/js/templates.js"></script>
+        <script src="/bg/js/japanese.js"></script>
         <script src="/fg/js/document.js"></script>
         <script src="/fg/js/source.js"></script>
         <script src="/mixed/js/audio.js"></script>
         <script src="/mixed/js/display-context.js"></script>
         <script src="/mixed/js/display.js"></script>
         <script src="/mixed/js/display-generator.js"></script>
-        <script src="/mixed/js/japanese.js"></script>
         <script src="/mixed/js/scroll.js"></script>
         <script src="/mixed/js/text-scanner.js"></script>
+        <script src="/mixed/js/template-handler.js"></script>
 
+        <script src="/bg/js/search-query-parser-generator.js"></script>
         <script src="/bg/js/search-query-parser.js"></script>
+        <script src="/bg/js/clipboard-monitor.js"></script>
         <script src="/bg/js/search.js"></script>
         <script src="/bg/js/search-frontend.js"></script>
     </body>
diff --git a/ext/bg/settings.html b/ext/bg/settings.html
index 3e06d4b5..b048a36c 100644
--- a/ext/bg/settings.html
+++ b/ext/bg/settings.html
@@ -134,6 +134,10 @@
                     <label><input type="checkbox" id="enable"> Enable content scanning</label>
                 </div>
 
+                <div class="checkbox" data-hide-for-browser="firefox-mobile">
+                    <label><input type="checkbox" id="enable-clipboard-popups"> Enable native popups when copying Japanese text</label>
+                </div>
+
                 <div class="checkbox">
                     <label><input type="checkbox" id="show-usage-guide"> Show usage guide on startup</label>
                 </div>
@@ -481,7 +485,7 @@
                 </p>
 
                 <div class="checkbox">
-                    <label><input type="checkbox" id="enable-search-within-first-popup"> Enable search when clicking glossary entries</label>
+                    <label><input type="checkbox" id="enable-search-within-first-popup"> Enable search when clicking glossary entries and tags</label>
                 </div>
 
                 <div class="checkbox">
@@ -492,6 +496,10 @@
                     <label><input type="checkbox" id="enable-scanning-of-popup-expressions"> Enable scanning of expressions in search results</label>
                 </div>
 
+                <div class="checkbox">
+                    <label><input type="checkbox" id="enable-search-tags"> Enable clickable and scannable tags for searching expressions and their readings</label>
+                </div>
+
                 <div class="form-group">
                     <label for="popup-nesting-max-depth">Maximum number of additional popups</label>
                     <input type="number" min="0" step="1" id="popup-nesting-max-depth" class="form-control">
@@ -760,6 +768,13 @@
 
                     <div class="alert alert-danger" id="anki-error" hidden></div>
 
+                    <div class="alert alert-danger" id="anki-invalid-response-error" hidden>
+                        Attempting to connect to Anki can sometimes return an error message which includes "Invalid response",
+                        which may indicate that the value of the <strong>Interface server</strong> option is incorrect.
+                        The <strong>Show advanced options</strong> checkbox under General Options must be ticked ticked to show this option.
+                        Resetting it to the default value may fix issues that are occurring.
+                    </div>
+
                     <div class="form-group">
                         <label for="card-tags">Card tags <span class="label-light">(comma or space separated)</span></label>
                         <input type="text" id="card-tags" class="form-control">
@@ -771,7 +786,7 @@
                     </div>
 
                     <div class="form-group options-advanced">
-                        <label for="interface-server">Interface server</label>
+                        <label for="interface-server">Interface server <span class="label-light">(Default: http://127.0.0.1:8765)</span></label>
                         <input type="text" id="interface-server" class="form-control">
                     </div>
 
@@ -1073,16 +1088,15 @@
         <script src="/mixed/js/core.js"></script>
         <script src="/mixed/js/dom.js"></script>
         <script src="/mixed/js/api.js"></script>
-        <script src="/mixed/js/japanese.js"></script>
 
         <script src="/bg/js/anki.js"></script>
         <script src="/bg/js/conditions.js"></script>
         <script src="/bg/js/dictionary.js"></script>
         <script src="/bg/js/handlebars.js"></script>
+        <script src="/bg/js/japanese.js"></script>
         <script src="/bg/js/options.js"></script>
         <script src="/bg/js/page-exit-prevention.js"></script>
         <script src="/bg/js/profile-conditions.js"></script>
-        <script src="/bg/js/templates.js"></script>
         <script src="/bg/js/util.js"></script>
         <script src="/mixed/js/audio.js"></script>