Modernizr Documentation
▻http://modernizr.com/docs
See Video for Everybody by Kroc Camen for a JavaScript-less way to use HTML5 video with graceful fallbacks for all browsers. With Modernizr’s video detection, you can use CSS and JavaScript styling to further enhance the look and/or interactivity when the browser does support video.
If video support is detected, Modernizr assesses which formats the current browser will play. Currently, Modernizr tests ogg, webm and h264.
Also, read the important note about audio formats above, as the same return values apply to video.