JS3 is a real-time CSS generator. It let's you code your CSS inside javascript and offers a rich object model to play around with style rules and other constructs within your programming environment. All changes are applied instantly unless instructed otherwise.
Breaking off the CSS from being a dead text that DOM interprets and apply, it adds life to CSS constructs by adding javascript accessibility to them.
If you are a new age JavaScript coder, you are going to love it.