I have developed a robust CSS selector engine for JavaScript with support for Selectors Level 4. It has a lot of options to make it highly customizable including custom pseudo-classes, custom prefixes with three levels of extended features, and it supports both domain and scope filtering (filtering the “normal” way and the querySelectorAll way). It’s cross-browser and lightning fast. Great for library developers or anyone who just wants a selector engine without the overhead of a full-blown library.
It’s the only selector engine to support the [url=http://www.w3.org/TR/selectors4/]Selectors Level 4 working draft
Check it out at [url]http://quicksand.joijs.com/
Comments welcome.