diff --git a/src/bg/js/agent.js b/src/bg/js/agent.js
index b3c4134..dfa8273 100644
--- a/src/bg/js/agent.js
+++ b/src/bg/js/agent.js
@@ -8,7 +8,7 @@ class Agent {
 
     onMessage(e) {
         const { action, params } = e.data;
-        if (action != 'callback' || !params || !params.callbackId)
+        if (action !== 'callback' || !params || !params.callbackId)
             return;
         // we are the sender getting the callback
         if (this.callbacks[params.callbackId] && typeof(this.callbacks[params.callbackId]) === 'function') {
@@ -18,7 +18,7 @@ class Agent {
     }
 
     postMessage(action, params, callback) {
-        if (action != 'callback' && callback) {
+        if (action !== 'callback' && callback) {
             params.callbackId = Math.random();
             this.callbacks[params.callbackId] = callback;
         }
diff --git a/src/bg/js/ankiconnect.js b/src/bg/js/ankiconnect.js
index b9e4099..da82f13 100644
--- a/src/bg/js/ankiconnect.js
+++ b/src/bg/js/ankiconnect.js
@@ -16,7 +16,7 @@ class Ankiconnect {
                 dataType: 'json',
                 success: (response) => {
                     try {
-                        if (Object.getOwnPropertyNames(response).length != 2) {
+                        if (Object.getOwnPropertyNames(response).length !== 2) {
                             throw 'response has an unexpected number of fields';
                         }
                         if (!response.hasOwnProperty('error')) {
diff --git a/src/bg/js/ankiweb.js b/src/bg/js/ankiweb.js
index 9572205..1490a2b 100644
--- a/src/bg/js/ankiweb.js
+++ b/src/bg/js/ankiweb.js
@@ -122,9 +122,9 @@ class Ankiweb {
     async getProfile(retryCount = 1, forceLogout = false) {
         try {
             let resp = await this.api_connect(forceLogout);
-            if (resp.action == 'edit') {
+            if (resp.action === 'edit') {
                 return resp.data;
-            } else if (retryCount > 0 && resp.action == 'login' && await this.api_login(this.id, this.password, resp.data)) {
+            } else if (retryCount > 0 && resp.action === 'login' && await this.api_login(this.id, this.password, resp.data)) {
                 return this.getProfile(retryCount - 1);
             } else {
                 return null;
diff --git a/src/bg/js/backend.js b/src/bg/js/backend.js
index c67e362..9552bde 100644
--- a/src/bg/js/backend.js
+++ b/src/bg/js/backend.js
@@ -28,7 +28,7 @@ class ODHBack {
     }
 
     onCommand(command) {
-        if (command != 'enabled') return;
+        if (command !== 'enabled') return;
         this.options.enabled = !this.options.enabled;
         this.setFrontendOptions(this.options);
         optionsSave(this.options);
diff --git a/src/bg/js/popup.js b/src/bg/js/popup.js
index 6813a73..2978c4d 100644
--- a/src/bg/js/popup.js
+++ b/src/bg/js/popup.js
@@ -1,6 +1,6 @@
 /* global odhback, localizeHtmlPage, utilAsync, optionsLoad, optionsSave */
 async function populateAnkiDeckAndModel(options) {
-    let names = [];
+    let names;
     $('#deckname').empty();
     names = await odhback().opt_getDeckNames();
     if (names !== null) {
diff --git a/src/fg/js/range.js b/src/fg/js/range.js
index b31eef4..e36688e 100644
--- a/src/fg/js/range.js
+++ b/src/fg/js/range.js
@@ -35,7 +35,7 @@ class TextSourceRange {
     }
 
     isAlpha(char) {
-        return /[\u002D|\u0041-\u005A|\u0061-\u007A|\u00A0-\u024F]/.test(char);
+        return /[\u002D|\u0041-\u005A\u0061-\u007A\u00A0-\u024F]/.test(char);
     }
 
     getStartPos(backwardcount) {
@@ -48,7 +48,7 @@ class TextSourceRange {
             clone.setStart(this.rng.startContainer, --pos);
             rangeText = clone.toString();
             count += this.isAlpha(rangeText.charAt(0)) ? 0 : 1;
-            if (count == backwardcount) {
+            if (count === backwardcount) {
                 break;
             }
         }
@@ -65,7 +65,7 @@ class TextSourceRange {
             clone.setEnd(this.rng.endContainer, ++pos);
             rangeText = clone.toString();
             count += this.isAlpha(rangeText.charAt(rangeText.length - 1)) ? 0 : 1;
-            if (count == forwardcount) {
+            if (count === forwardcount) {
                 break;
             }
         }
@@ -74,7 +74,7 @@ class TextSourceRange {
 
     setStartOffset(backwardcount) {
         let startPos = this.getStartPos(backwardcount);
-        if (startPos != 0)
+        if (startPos !== 0)
             startPos++;
         this.rng.setStart(this.rng.startContainer, startPos);
 
@@ -82,7 +82,7 @@ class TextSourceRange {
 
     setEndOffset(forwardcount) {
         let endPos = this.getEndPos(forwardcount);
-        if (endPos != this.rng.endContainer.data.length)
+        if (endPos !== this.rng.endContainer.data.length)
             endPos--;
         this.rng.setEnd(this.rng.endContainer, endPos);
     }