I haven’t used AdBlock+ for quite a while… ever since I entered the realm of Flash-less web browsing thanks to Adobe’s inability to produce a 64 bit Windows version of the Flash plugin. However when Beta 1 of Firefox 4 was released I had to answer the question “Does AdBlock+ work?” quite often (the nightly does), so I more or less had to install it.
I used the opportunity to get rid of the biggest annoyance of YouTube’s HTML5 player: the broken full screen mode. YouTube overlays the video with a transparent div in order to block users from right-clicking on a video, since this offers the option to save the video (YouTube’s videos may be free, but they are still copyrighted and you don’t automatically get the right to distribute them).
Getting rid of this overlay with AdBlock+ is easy since it has a unique class attribute: “video-blocker”. Just Go to AdBlock+ preferences window (Tools -> Adblock Plus Preferences…), click “Add filter…” in the lower right and enter the selector “youtube.com##.video-blocker” (without quotes). This hides the overlay and you’re now free to right click on any YouTube HTML5 video to access the fullscreen option.
Here’s a link to the Coraline trailer: Try it. Link.
Using the real full screen mode instead of YouTube’s normal pseudo full-screen mode also means that Firefox can now use hardware acceleration (via OpenGL and Direct3D), even if you don’t have Direct2D enabled. Even my old laptop can play HD WebM video this way.