diff --git a/youtube/templates/watch.html b/youtube/templates/watch.html
index 47880b8..798e783 100644
--- a/youtube/templates/watch.html
+++ b/youtube/templates/watch.html
@@ -184,7 +184,7 @@
                          // IntersectionObserver isn't supported in pre-quantum
                          // firefox versions, but the alternative of making it
                          // manually is a performance drain, so oh well
-                         var observer = new IntersectionObserver(lazyLoad, {
+                         let observer = new IntersectionObserver(lazyLoad, {
 
                              // where in relation to the edge of the viewport, we are observing
                              rootMargin: "100px",
@@ -205,7 +205,7 @@
                          };
 
                          // Tell our observer to observe all img elements with a "lazy" class
-                         var lazyImages = document.querySelectorAll('img.lazy');
+                         let lazyImages = document.querySelectorAll('img.lazy');
                          lazyImages.forEach(img => {
                              observer.observe(img);
                          });
@@ -220,7 +220,7 @@
             {% if settings.related_videos_mode != 0 or playlist %}
                 <script>
                  // @license magnet:?xt=urn:btih:0b31508aeb0634b347b8270c7bee4d411b5d4109&dn=agpl-3.0.txt AGPL-v3-or-Later
-                 var playability_error = {{ 'true' if playability_error else 'false' }};
+                 let playability_error = {{ 'true' if playability_error else 'false' }};
                  {% if playlist and playlist['current_index'] is not none %}
                  {% set isPlaylist = true %}
                  {% endif %}
@@ -230,7 +230,7 @@
                  function escapeRegExp(string) {
                      return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
                  }
-                 var playlist_id = {{ playlist['id']|tojson }};
+                 let playlist_id = {{ playlist['id']|tojson }};
                  playlist_id = escapeRegExp(playlist_id);
                  {% endif %}
 
@@ -238,14 +238,14 @@
                  // pain in the ass:
                  // https://developer.mozilla.org/en-US/docs/Web/API/Document/cookie
                  {% if isPlaylist %}
-                 var cookieValue = document.cookie.replace(new RegExp(
+                 let cookieValue = document.cookie.replace(new RegExp(
                      '(?:(?:^|.*;\\s*)autoplay_' + playlist_id + '\\s*\\=\\s*([^;]*).*$)|^.*$'), '$1');
                  {% else %}
-                 var cookieValue = document.cookie.replace(new RegExp(
+                 let cookieValue = document.cookie.replace(new RegExp(
                      '(?:(?:^|.*;\\s*)autoplay\\s*\\=\\s*([^;]*).*$)|^.*$'), '$1');
                  {% endif %}
 
-                 var autoplayEnabled = 0;
+                 let autoplayEnabled = 0;
                  if(cookieValue.length === 0){
                      autoplayEnabled = 0;
                  } else {
@@ -253,13 +253,13 @@
                  }
 
                  // check the checkbox if autoplay is on
-                 var checkbox = document.querySelector('#autoplay-toggle');
+                 let checkbox = document.querySelector('#autoplay-toggle');
                  if(autoplayEnabled){
                      checkbox.checked = true;
                  }
 
                  // listen for checkbox to turn autoplay on and off
-                 var cookie = 'autoplay'
+                 let cookie = 'autoplay'
                  {% if isPlaylist %}
                  cookie += '_' + playlist_id;
                  {% endif %}
@@ -275,7 +275,7 @@
 
                  if(!playability_error){
                      // play the video if autoplay is on
-                     var vid = document.querySelector('video');
+                     let vid = document.querySelector('video');
                      if(autoplayEnabled){
                          vid.play();
                      }
@@ -283,25 +283,25 @@
 
                  // determine next video url
                  {% if isPlaylist %}
-                 var currentIndex = {{ playlist['current_index']|tojson }};
+                 let currentIndex = {{ playlist['current_index']|tojson }};
                  {% if playlist['current_index']+1 == playlist['items']|length %}
-                 var nextVideoUrl = null;
+                 let nextVideoUrl = null;
                  {% else %}
-                 var nextVideoUrl = {{ (playlist['items'][playlist['current_index']+1]['url'])|tojson }};
+                 let nextVideoUrl = {{ (playlist['items'][playlist['current_index']+1]['url'])|tojson }};
                  {% endif %}
 
                  // scroll playlist to proper position
                  // item height + gap == 100
-                 var pl = document.querySelector('.playlist-videos');
+                 let pl = document.querySelector('.playlist-videos');
                  pl.scrollTop = 100*currentIndex;
                  {% else %}
                  {% if related|length == 0 %}
-                 var nextVideoUrl = null;
+                 let nextVideoUrl = null;
                  {% else %}
-                 var nextVideoUrl = {{ (related[0]['url'])|tojson }};
+                 let nextVideoUrl = {{ (related[0]['url'])|tojson }};
                  {% endif %}
                  {% endif %}
-                 var nextVideoDelay = 1000;
+                 let nextVideoDelay = 1000;
 
                  // go to next video when video ends
                  // https://stackoverflow.com/a/2880950