requestAnimationFrame polyfill

rAF.js

// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

// requestAnimationFrame polyfill by Erik Möller
// fixes from Paul Irish and Tino Zijdel

(function() {
    var lastTime = 0;
    var vendors = ['ms', 'moz', 'webkit', 'o'];
    for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
        window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
        window.cancelAnimationFrame = window[vendors[x]+'CancelAnimationFrame'] 
                                   || window[vendors[x]+'RequestCancelAnimationFrame'];
    }
 
    if (!window.requestAnimationFrame || !window.cancelAnimationFrame) //current Chrome (16) supports request but not cancel 
        window.requestAnimationFrame = function(callback, element) {
            var currTime = new Date().getTime();
            var timeToCall = Math.max(0, 16 - (currTime - lastTime));
            var id = window.setTimeout(function() { callback(currTime + timeToCall); }, 
              timeToCall);
            lastTime = currTime + timeToCall;
            return id;
        };
 
    if (!window.cancelAnimationFrame)
        window.cancelAnimationFrame = function(id) {
            clearTimeout(id);
        };
}());

line 16 fixes issue with Chrome 16 not supporting the cancelAnimationFrame

Whatchu talkin about.. Chrome 16 has webkitCancelRequestAnimationFrame

http://jsfiddle.net/XQpzU/2117/show/ and run webkitCancelRequestAnimationFrame(rid) in console.

What the junk, you're right. I swear I tested it and double checked my spelling. My bad. Deleting this gist.
/facepalm