A Bookmarklet to Set a Theatre Mode for YouTube Live videos.

yt_theatre_bookmarklet.js

javascript:(function() { var video = document.querySelector('.html5-video-container > video.video-stream.html5-main-video'); video.style.width = '100%'; video.style.height = 'auto'; var columns = document.querySelector('#columns.style-scope.ytd-watch-flexy'); columns.style.maxWidth = 'initial'; var chat = document.querySelector('#chat.style-scope.ytd-watch-flexy'); chat.style.height = '90vh';})();

If you want to use this Bookmarklet:

1. Create a new Bookmark in Chrome (I have only confirmed Chrome support).
2. In the URL for the bookmark, paste the above code.
3. When you go to a YouTube Live video, click the bookmark and your layout will be adjusted.

This will reset on page refresh, so you will have to click it each time you want the layout.

Enjoy!

If you're from YouTube... here's a clean version.

(function() {
  var video = document.querySelector('.html5-video-container > video.video-stream.html5-main-video');
  video.style.width = '100%';
  video.style.height = 'auto';
  
  var columns = document.querySelector('#columns.style-scope.ytd-watch-flexy');
  columns.style.maxWidth = 'initial';

  var chat = document.querySelector('#chat.style-scope.ytd-watch-flexy');
  chat.style.height = '90vh';
})();