I read in the Inquirer and elsewhere that YouTube uses HTML5 by default in some players, including beta Firefox. What does that mean? What is the case with Firefox 36?

How can one tell when HTML5 is used (no matter the browser)?

2 Answers 2


Right-click the video when it is playing or not and the context menu that pops up will tell you if you are using Adobe Flash Player or the YouTube HTML5 Video Player.

This is the right-click menu for the two cases:

In Firefox 36:

enter image description here

Google Chrome 41.0:

enter image description here

You can find out if you are using YouTube HTML5 Video Player as the default player for playing YouTube videos by opening a new web browser tab and visiting the YouTube HTML5 Video Player webpage from the new browser tab.

YouTube HTML5 Video Player is the default player for playing YouTube videos on most popular Web browsers such as Chrome, Safari 8, IE 11 and in some beta versions of Firefox, but not in Firefox 36, 37, 38 or Firefox 39. Starting with Firefox 40, the YouTube HTML5 Video Player is the default video player for playing YouTube videos. The gist of this YouTube Developers and Engineers Blog article is that the YouTube HTML5 Video Player is now the better YouTube video player and the precursor of even better things to come.

  • For the the moment (March 2015) Firefox beta version is 37, and that is still using flash as youtube default. Firefox 38, developer version, is using HTML5. Another browser I tested in Linux, Midori 0.5.9 (which uses the WebKit rendering engine), is not displaying the explicit context menu as in the image above but, while youtube is playing, the YouTube HTML5 Video Player says "The HTML5 player is currently used when possible"
    – user47949
    Mar 30, 2015 at 22:47
  • I guess a solution to know for sure that Firefox is rendering in HTML5 is to install an addon like HTML Video everywhere
    – user47949
    Mar 30, 2015 at 22:50

This is just to show how to use HTML5 on youtube in Firefox.

Install HTML5 Video Everywhere! addon.

Go to https://www.youtube.com/html5.

Request HTML5 player.

enter image description here

After that refresh the youtube video and right click on the video to see the type of player as shown in the main answer.

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