haz.io gives you a quick overview about your browser’s support for recent technologies in the world of HTML, CSS and Javascript.
Using Modernizr in the backend, it detects which HTML5 and CSS3 are supported, shows the result in a nice interface and links to the related W3C or WHATWG page for each property.
Haz.io is an open source project where you can get the source and update/improve it.
Website: http://haz.io/
Download: http://github.com/philippbosch/haz