Whenever you visit YouTube or any video sharing site, and try to play a video in full screen, a message appears on top saying ‘YouTube is now fullscreen. Press Esc at any time to exit.’ When you click ‘Allow’ or ‘deny’ button, and check ‘Remember decision for YouTube.com’, the same popup appears again for another video when played in fullscreen, that’s annoying, let us see how to disable this Youtube.com is now in the full screen popup in Firefox.

annoying Youtube is fullscreen popup-min

Google makes HTML5 Player default for Playing Videos on YouTube in Chrome and Firefox

UPDATE 1Firefox 43: Mozilla makes Full Screen Messages for YouTube Videos Less Annoying

UPDATE 2Firefox 43+: Remove ‘youtube.com is now full screen’ notification

Disable ‘youtube.com is now fullscreen’ popup in Firefox browser

1. Visit about:config

2. Find full-screen-api.approval-required preference and change its value to ‘false’.

Enable Media Source Extensions in Firefox for a better YouTube Player

Is this working for you? Is there any way to disable the same in Chrome?