10 files changed, 67 insertions, 70 deletions
diff --git a/ext/bg/js/settings/anki-templates.js b/ext/bg/js/settings/anki-templates.js
index 2e80e334..770716d4 100644
--- a/ext/bg/js/settings/anki-templates.js
+++ b/ext/bg/js/settings/anki-templates.js
@@ -45,10 +45,10 @@ function ankiTemplatesInitialize() {
         node.addEventListener('click', onAnkiTemplateMarkerClicked, false);
     }
 
-    $('#field-templates').on('change', (e) => onAnkiFieldTemplatesChanged(e));
-    $('#field-template-render').on('click', (e) => onAnkiTemplateRender(e));
-    $('#field-templates-reset').on('click', (e) => onAnkiFieldTemplatesReset(e));
-    $('#field-templates-reset-confirm').on('click', (e) => onAnkiFieldTemplatesResetConfirm(e));
+    $('#field-templates').on('change', onAnkiFieldTemplatesChanged);
+    $('#field-template-render').on('click', onAnkiTemplateRender);
+    $('#field-templates-reset').on('click', onAnkiFieldTemplatesReset);
+    $('#field-templates-reset-confirm').on('click', onAnkiFieldTemplatesResetConfirm);
 
     ankiTemplatesUpdateValue();
 }
diff --git a/ext/bg/js/settings/anki.js b/ext/bg/js/settings/anki.js
index 4263fc51..782691ab 100644
--- a/ext/bg/js/settings/anki.js
+++ b/ext/bg/js/settings/anki.js
@@ -154,10 +154,10 @@ async function _ankiFieldsPopulate(tabId, options) {
     container.appendChild(fragment);
 
     for (const node of container.querySelectorAll('.anki-field-value')) {
-        node.addEventListener('change', (e) => onFormOptionsChanged(e), false);
+        node.addEventListener('change', onFormOptionsChanged, false);
     }
     for (const node of container.querySelectorAll('.marker-link')) {
-        node.addEventListener('click', (e) => _onAnkiMarkerClicked(e), false);
+        node.addEventListener('click', _onAnkiMarkerClicked, false);
     }
 }
 
@@ -267,7 +267,7 @@ function ankiGetFieldMarkers(type) {
 
 function ankiInitialize() {
     for (const node of document.querySelectorAll('#anki-terms-model,#anki-kanji-model')) {
-        node.addEventListener('change', (e) => _onAnkiModelChanged(e), false);
+        node.addEventListener('change', _onAnkiModelChanged, false);
     }
 }
 
diff --git a/ext/bg/js/settings/audio-ui.js b/ext/bg/js/settings/audio-ui.js
index 555380b4..206539a4 100644
--- a/ext/bg/js/settings/audio-ui.js
+++ b/ext/bg/js/settings/audio-ui.js
@@ -37,7 +37,7 @@ AudioSourceUI.Container = class Container {
             this.children.push(new AudioSourceUI.AudioSource(this, audioSource, this.children.length));
         }
 
-        this._clickListener = () => this.onAddAudioSource();
+        this._clickListener = this.onAddAudioSource.bind(this);
         this.addButton.addEventListener('click', this._clickListener, false);
     }
 
@@ -105,8 +105,8 @@ AudioSourceUI.AudioSource = class AudioSource {
 
         this.select.value = audioSource;
 
-        this._selectChangeListener = () => this.onSelectChanged();
-        this._removeClickListener = () => this.onRemoveClicked();
+        this._selectChangeListener = this.onSelectChanged.bind(this);
+        this._removeClickListener = this.onRemoveClicked.bind(this);
 
         this.select.addEventListener('change', this._selectChangeListener, false);
         this.removeButton.addEventListener('click', this._removeClickListener, false);
diff --git a/ext/bg/js/settings/audio.js b/ext/bg/js/settings/audio.js
index 588d9a11..6d183a43 100644
--- a/ext/bg/js/settings/audio.js
+++ b/ext/bg/js/settings/audio.js
@@ -29,7 +29,7 @@ async function audioSettingsInitialize() {
         document.querySelector('.audio-source-list'),
         document.querySelector('.audio-source-add')
     );
-    audioSourceUI.save = () => settingsSaveOptions();
+    audioSourceUI.save = settingsSaveOptions;
 
     textToSpeechInitialize();
 }
@@ -37,11 +37,11 @@ async function audioSettingsInitialize() {
 function textToSpeechInitialize() {
     if (typeof speechSynthesis === 'undefined') { return; }
 
-    speechSynthesis.addEventListener('voiceschanged', () => updateTextToSpeechVoices(), false);
+    speechSynthesis.addEventListener('voiceschanged', updateTextToSpeechVoices, false);
     updateTextToSpeechVoices();
 
-    document.querySelector('#text-to-speech-voice').addEventListener('change', (e) => onTextToSpeechVoiceChange(e), false);
-    document.querySelector('#text-to-speech-voice-test').addEventListener('click', () => textToSpeechTest(), false);
+    document.querySelector('#text-to-speech-voice').addEventListener('change', onTextToSpeechVoiceChange, false);
+    document.querySelector('#text-to-speech-voice-test').addEventListener('click', textToSpeechTest, false);
 }
 
 function updateTextToSpeechVoices() {
diff --git a/ext/bg/js/settings/conditions-ui.js b/ext/bg/js/settings/conditions-ui.js
index 5a271321..4ca86b07 100644
--- a/ext/bg/js/settings/conditions-ui.js
+++ b/ext/bg/js/settings/conditions-ui.js
@@ -41,7 +41,7 @@ ConditionsUI.Container = class Container {
             this.children.push(new ConditionsUI.ConditionGroup(this, conditionGroup));
         }
 
-        this.addButton.on('click', () => this.onAddConditionGroup());
+        this.addButton.on('click', this.onAddConditionGroup.bind(this));
     }
 
     cleanup() {
@@ -127,7 +127,7 @@ ConditionsUI.ConditionGroup = class ConditionGroup {
             this.children.push(new ConditionsUI.Condition(this, condition));
         }
 
-        this.addButton.on('click', () => this.onAddCondition());
+        this.addButton.on('click', this.onAddCondition.bind(this));
     }
 
     cleanup() {
@@ -185,10 +185,10 @@ ConditionsUI.Condition = class Condition {
         this.updateOperators();
         this.updateInput();
 
-        this.input.on('change', () => this.onInputChanged());
-        this.typeSelect.on('change', () => this.onConditionTypeChanged());
-        this.operatorSelect.on('change', () => this.onConditionOperatorChanged());
-        this.removeButton.on('click', () => this.onRemoveClicked());
+        this.input.on('change', this.onInputChanged.bind(this));
+        this.typeSelect.on('change', this.onConditionTypeChanged.bind(this));
+        this.operatorSelect.on('change', this.onConditionOperatorChanged.bind(this));
+        this.removeButton.on('click', this.onRemoveClicked.bind(this));
     }
 
     cleanup() {
@@ -235,10 +235,10 @@ ConditionsUI.Condition = class Condition {
     updateInput() {
         const conditionDescriptors = this.parent.parent.conditionDescriptors;
         const {type, operator} = this.condition;
-        const props = {
-            placeholder: '',
-            type: 'text'
-        };
+        const props = new Map([
+            ['placeholder', ''],
+            ['type', 'text']
+        ]);
 
         const objects = [];
         if (hasOwn(conditionDescriptors, type)) {
@@ -252,20 +252,20 @@ ConditionsUI.Condition = class Condition {
 
         for (const object of objects) {
             if (hasOwn(object, 'placeholder')) {
-                props.placeholder = object.placeholder;
+                props.set('placeholder', object.placeholder);
             }
             if (object.type === 'number') {
-                props.type = 'number';
+                props.set('type', 'number');
                 for (const prop of ['step', 'min', 'max']) {
                     if (hasOwn(object, prop)) {
-                        props[prop] = object[prop];
+                        props.set(prop, object[prop]);
                     }
                 }
             }
         }
 
-        for (const prop in props) {
-            this.input.prop(prop, props[prop]);
+        for (const [prop, value] of props.entries()) {
+            this.input.prop(prop, value);
         }
 
         const {valid} = this.validateValue(this.condition.value);
diff --git a/ext/bg/js/settings/dictionaries.js b/ext/bg/js/settings/dictionaries.js
index 70a22a16..b9551073 100644
--- a/ext/bg/js/settings/dictionaries.js
+++ b/ext/bg/js/settings/dictionaries.js
@@ -36,7 +36,7 @@ class SettingsDictionaryListUI {
         this.dictionaryEntries = [];
         this.extra = null;
 
-        document.querySelector('#dict-delete-confirm').addEventListener('click', (e) => this.onDictionaryConfirmDelete(e), false);
+        document.querySelector('#dict-delete-confirm').addEventListener('click', this.onDictionaryConfirmDelete.bind(this), false);
     }
 
     setOptionsDictionaries(optionsDictionaries) {
@@ -198,10 +198,10 @@ class SettingsDictionaryEntryUI {
 
         this.applyValues();
 
-        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);
+        this.eventListeners.addEventListener(this.enabledCheckbox, 'change', this.onEnabledChanged.bind(this), false);
+        this.eventListeners.addEventListener(this.allowSecondarySearchesCheckbox, 'change', this.onAllowSecondarySearchesChanged.bind(this), false);
+        this.eventListeners.addEventListener(this.priorityInput, 'change', this.onPriorityChanged.bind(this), false);
+        this.eventListeners.addEventListener(this.deleteButton, 'click', this.onDeleteButtonClicked.bind(this), false);
     }
 
     cleanup() {
@@ -341,14 +341,14 @@ async function dictSettingsInitialize() {
         document.querySelector('#dict-groups-extra'),
         document.querySelector('#dict-extra-template')
     );
-    dictionaryUI.save = () => settingsSaveOptions();
-
-    document.querySelector('#dict-purge-button').addEventListener('click', (e) => onDictionaryPurgeButtonClick(e), false);
-    document.querySelector('#dict-purge-confirm').addEventListener('click', (e) => onDictionaryPurge(e), false);
-    document.querySelector('#dict-file-button').addEventListener('click', (e) => onDictionaryImportButtonClick(e), false);
-    document.querySelector('#dict-file').addEventListener('change', (e) => onDictionaryImport(e), false);
-    document.querySelector('#dict-main').addEventListener('change', (e) => onDictionaryMainChanged(e), false);
-    document.querySelector('#database-enable-prefix-wildcard-searches').addEventListener('change', (e) => onDatabaseEnablePrefixWildcardSearchesChanged(e), false);
+    dictionaryUI.save = settingsSaveOptions;
+
+    document.querySelector('#dict-purge-button').addEventListener('click', onDictionaryPurgeButtonClick, false);
+    document.querySelector('#dict-purge-confirm').addEventListener('click', onDictionaryPurge, false);
+    document.querySelector('#dict-file-button').addEventListener('click', onDictionaryImportButtonClick, false);
+    document.querySelector('#dict-file').addEventListener('change', onDictionaryImport, false);
+    document.querySelector('#dict-main').addEventListener('change', onDictionaryMainChanged, false);
+    document.querySelector('#database-enable-prefix-wildcard-searches').addEventListener('change', onDatabaseEnablePrefixWildcardSearchesChanged, false);
 
     await onDictionaryOptionsChanged();
     await onDatabaseUpdated();
diff --git a/ext/bg/js/settings/main.js b/ext/bg/js/settings/main.js
index c6683427..127a6d2b 100644
--- a/ext/bg/js/settings/main.js
+++ b/ext/bg/js/settings/main.js
@@ -68,7 +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();
@@ -200,7 +200,7 @@ async function formWrite(options) {
 }
 
 function formSetupEventListeners() {
-    $('input, select, textarea').not('.anki-model').not('.ignore-form-changes *').change((e) => onFormOptionsChanged(e));
+    $('input, select, textarea').not('.anki-model').not('.ignore-form-changes *').change(onFormOptionsChanged);
 }
 
 function formUpdateVisibility(options) {
diff --git a/ext/bg/js/settings/popup-preview-frame.js b/ext/bg/js/settings/popup-preview-frame.js
index aa2b6100..1ceac177 100644
--- a/ext/bg/js/settings/popup-preview-frame.js
+++ b/ext/bg/js/settings/popup-preview-frame.js
@@ -28,6 +28,12 @@ class SettingsPopupPreview {
         this.themeChangeTimeout = null;
         this.textSource = null;
         this._targetOrigin = chrome.runtime.getURL('/').replace(/\/$/, '');
+
+        this._windowMessageHandlers = new Map([
+            ['setText', ({text}) => this.setText(text)],
+            ['setCustomCss', ({css}) => this.setCustomCss(css)],
+            ['setCustomOuterCss', ({css}) => this.setCustomOuterCss(css)]
+        ]);
     }
 
     static create() {
@@ -38,15 +44,12 @@ class SettingsPopupPreview {
 
     async prepare() {
         // Setup events
-        window.addEventListener('message', (e) => this.onMessage(e), false);
+        window.addEventListener('message', this.onMessage.bind(this), false);
 
-        const themeDarkCheckbox = document.querySelector('#theme-dark-checkbox');
-        if (themeDarkCheckbox !== null) {
-            themeDarkCheckbox.addEventListener('change', () => this.onThemeDarkCheckboxChanged(themeDarkCheckbox), false);
-        }
+        document.querySelector('#theme-dark-checkbox').addEventListener('change', this.onThemeDarkCheckboxChanged.bind(this), false);
 
         // Overwrite API functions
-        window.apiOptionsGet = (...args) => this.apiOptionsGet(...args);
+        window.apiOptionsGet = this.apiOptionsGet.bind(this);
 
         // Overwrite frontend
         const popupHost = new PopupProxyHost();
@@ -56,7 +59,7 @@ class SettingsPopupPreview {
         this.popup.setChildrenSupported(false);
 
         this.popupSetCustomOuterCssOld = this.popup.setCustomOuterCss;
-        this.popup.setCustomOuterCss = (...args) => this.popupSetCustomOuterCss(...args);
+        this.popup.setCustomOuterCss = this.popupSetCustomOuterCss.bind(this);
 
         this.frontend = new Frontend(this.popup);
 
@@ -101,14 +104,14 @@ class SettingsPopupPreview {
         if (e.origin !== this._targetOrigin) { return; }
 
         const {action, params} = e.data;
-        const handler = SettingsPopupPreview._messageHandlers.get(action);
+        const handler = this._windowMessageHandlers.get(action);
         if (typeof handler !== 'function') { return; }
 
-        handler(this, params);
+        handler(params);
     }
 
-    onThemeDarkCheckboxChanged(node) {
-        document.documentElement.classList.toggle('dark', node.checked);
+    onThemeDarkCheckboxChanged(e) {
+        document.documentElement.classList.toggle('dark', e.target.checked);
         if (this.themeChangeTimeout !== null) {
             clearTimeout(this.themeChangeTimeout);
         }
@@ -171,12 +174,6 @@ class SettingsPopupPreview {
     }
 }
 
-SettingsPopupPreview._messageHandlers = new Map([
-    ['setText', (self, {text}) => self.setText(text)],
-    ['setCustomCss', (self, {css}) => self.setCustomCss(css)],
-    ['setCustomOuterCss', (self, {css}) => self.setCustomOuterCss(css)]
-]);
-
 SettingsPopupPreview.instance = SettingsPopupPreview.create();
 
 
diff --git a/ext/bg/js/settings/profiles.js b/ext/bg/js/settings/profiles.js
index 3e589809..f946a33a 100644
--- a/ext/bg/js/settings/profiles.js
+++ b/ext/bg/js/settings/profiles.js
@@ -39,16 +39,16 @@ async function profileOptionsSetup() {
 }
 
 function profileOptionsSetupEventListeners() {
-    $('#profile-target').change((e) => onTargetProfileChanged(e));
-    $('#profile-name').change((e) => onProfileNameChanged(e));
-    $('#profile-add').click((e) => onProfileAdd(e));
-    $('#profile-remove').click((e) => onProfileRemove(e));
-    $('#profile-remove-confirm').click((e) => onProfileRemoveConfirm(e));
-    $('#profile-copy').click((e) => onProfileCopy(e));
-    $('#profile-copy-confirm').click((e) => onProfileCopyConfirm(e));
+    $('#profile-target').change(onTargetProfileChanged);
+    $('#profile-name').change(onProfileNameChanged);
+    $('#profile-add').click(onProfileAdd);
+    $('#profile-remove').click(onProfileRemove);
+    $('#profile-remove-confirm').click(onProfileRemoveConfirm);
+    $('#profile-copy').click(onProfileCopy);
+    $('#profile-copy-confirm').click(onProfileCopyConfirm);
     $('#profile-move-up').click(() => onProfileMove(-1));
     $('#profile-move-down').click(() => onProfileMove(1));
-    $('.profile-form').find('input, select, textarea').not('.profile-form-manual').change((e) => onProfileOptionsChanged(e));
+    $('.profile-form').find('input, select, textarea').not('.profile-form-manual').change(onProfileOptionsChanged);
 }
 
 function tryGetIntegerValue(selector, min, max) {
diff --git a/ext/bg/js/settings/storage.js b/ext/bg/js/settings/storage.js
index cbe1bb4d..8978414e 100644
--- a/ext/bg/js/settings/storage.js
+++ b/ext/bg/js/settings/storage.js
@@ -57,7 +57,7 @@ async function storageInfoInitialize() {
 
     await storageShowInfo();
 
-    document.querySelector('#storage-refresh').addEventListener('click', () => storageShowInfo(), false);
+    document.querySelector('#storage-refresh').addEventListener('click', storageShowInfo, false);
 }
 
 async function storageUpdateStats() {