Modernizr - Detect CSS3 and HTML5 Features Available
Modernizr is a script that will detect native CSS3 and HTML5 features available in the current UA and provide an object containing all features with a true/false value, depending on whether the UA has native support for it or not.
Modernizr helps you take advantage of emerging web technologies (CSS3, HTML 5) while still maintaining a fine level of control over older browsers that may not yet support these new technologies.
In addition to that, Modernizr will add classes to the element of the page, one for each cutting-edge feature. If the UA supports it, a class like cssgradients will be added. If not, the class name will be no-cssgradients. This allows for simple if-conditionals in CSS styling, making it easily to have fine control over the look and feel of your website.
Requirements:-
Demo: http://modernizr.github.com/Modernizr/output.html
License: BSD and MIT licenses