Dive Into HTML 5 : Detecting HTML 5 Features
Dive Into HTML 5
You may well ask: "How can I start using HTML 5 if older browsers don't support it?" But the question itself is misleading. HTML 5 is not one big thing; it is a collection of individual features. So you can't detect "HTML 5 support," because that doesn't make any sense. But you can detect support for individual features, like canvas, video, or geolocation.
