I have set Flash to "ask to activate". Now Youtube does not load the video. How can I make Youtube use the HTML5 player?
Simply go to http://www.youtube.com/html5 and scroll down a bit to find "Request the HTML5 Player" button.
This should make YouTube use the HTML5 player instead of the Flash Player.
Start by installing a media player plug-in for Firefox. Personally I prefer the tighter VLC:
sudo apt-get install browser-plugin-vlc
Restart Firefox and then access this web page:
There activate the checkbox "The HTML5 player is currently used when possible."
You can go here: https://www.youtube.com/html5?gl=EN
and set the HTML5 player instead of the default flash player