This is something I've been meaning to do for a while, and hove only just got around to. PreParse is a Javascript and CSS preprocessor. Write standards compliant CSS and preparse will modify it to suit the clients browser.

Javascript... well, that's a whole nother thing. How about proper class declaration? <<<EOT strings? Including server-side functions in client side scripting? Or getting rid of object and browser detection?

PreParse does all this for you, you just write the code, and PreParse makes it work!

Check it out here, and read the full documentation here.