diff --git a/.eslintrc.js b/.eslintrc.js
index 1c044e1..72398fc 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -7,6 +7,10 @@ module.exports = {
   env: {
     browser: true,
   },
+  globals: {
+    browser: 'readonly',
+    chrome: 'readonly',
+  },
   rules: {
     strict: ['error', 'global'],
     'no-unused-vars': ['error', { vars: 'local' }],
diff --git a/extension/background.js b/extension/background.js
index 7aede90..745d6ef 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -2,6 +2,8 @@
 extension background script listening for events
 */
 
+'use strict';
+
 console.log('running background.js');
 
 let browserType = getBrowser();
diff --git a/extension/popup.js b/extension/popup.js
index 1e59401..9e591d5 100644
--- a/extension/popup.js
+++ b/extension/popup.js
@@ -2,6 +2,8 @@
 Loaded into popup index.html
 */
 
+'use strict';
+
 let browserType = getBrowser();
 
 // boilerplate to dedect browser type api
@@ -124,7 +126,7 @@ function setCookieState() {
 // change status icon based on connection status
 function setStatusIcon(connected) {
   let statusIcon = document.getElementById('status-icon');
-  if (connected == true) {
+  if (connected) {
     statusIcon.innerHTML = '☑';
     statusIcon.style.color = 'green';
   } else {
@@ -161,10 +163,6 @@ document.addEventListener('DOMContentLoaded', async () => {
     setCookieState();
   }
 
-  function onError(error) {
-    console.log(`Error: ${error}`);
-  }
-
   browserType.storage.local.get('access', function (result) {
     onGot(result);
   });
diff --git a/extension/script.js b/extension/script.js
index 756429c..9f58ce7 100644
--- a/extension/script.js
+++ b/extension/script.js
@@ -2,6 +2,8 @@
 content script running on youtube.com
 */
 
+'use strict';
+
 let browserType = getBrowser();
 
 // boilerplate to dedect browser type api
@@ -129,7 +131,7 @@ function buildSubLink(channelContainer) {
   });
   subLink.addEventListener('mouseover', e => {
     let subText;
-    if (window.location.pathname == '/watch') {
+    if (window.location.pathname === '/watch') {
       let currentLocation = window.location.href;
       subText = currentLocation;
     } else {
@@ -165,7 +167,7 @@ function buildDlLink(channelContainer) {
   });
   dlLink.addEventListener('mouseover', e => {
     let subText;
-    if (window.location.pathname == '/watch') {
+    if (window.location.pathname === '/watch') {
       let currentLocation = window.location.href;
       subText = currentLocation;
     } else {
@@ -231,7 +233,7 @@ function buildVideoButton(thumbContainer) {
     let videoTitle = thumbContainer.href;
     e.target.title = 'TA download: ' + videoTitle;
   });
-  dlButton.addEventListener('mouseout', e => {
+  dlButton.addEventListener('mouseout', () => {
     Object.assign(dlButton.style, {
       opacity: 0,
     });
@@ -321,7 +323,7 @@ function buttonError(button) {
   buttonSpan.style.color = 'red';
 
   button.style.opacity = 1;
-  button.addEventListener('mouseout', e => {
+  button.addEventListener('mouseout', () => {
     Object.assign(button.style, {
       opacity: 1,
     });