# Super fast css selector engine with CSS4 selector API support ## Goal - Support CSS3 as well as part of CSS4 selector API - Be lightweight - Be fastest - Be customizable - Optimised for IE < 8 ## Shims - document.querySelector - document.querySelectorAll - document.getElementsByClassName for IE < 9 - document.documentElement.querySelector - document.documentElement.querySelectorAll - document.documentElement.getElementsByClassName - document.documentElement.matchesSelector - document.documentElement.matches - Element.prototype.querySelector - Element.prototype.querySelectorAll - Element.prototype.getElementsByClassName for IE < 9 - Element.prototype.matchesSelector - Element.prototype.matches ## CSS4 Supporting selectors ### Subject of a selector ```javascript document.querySelector("div! a[href*=twitter]");// div that has **a** element with _href_ attribute that contains "twitter" document.querySelectorAll("body footer! div");// NodeList:[footer], if