requestAnimationFrame rAF

raf.js

 /** 
  * requestAnimationFrame polyfill
  * Based on: https://gist.github.com/paulirish/1579671
  * Tweaked by: Bradley - https://gist.github.com/bradley
  */
 (function() {
   var lastTime = 0,
     vendors = ['ms', 'moz', 'webkit', 'o'],
     x,
     length,
     currTime,
     timeToCall;

   for (x = 0, length = vendors.length; x < length && !window.requestAnimationFrame; ++x) {
     window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
     window.cancelAnimationFrame =
       window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame'];
   }

   if (!window.requestAnimationFrame) {
     window.requestAnimationFrame = function(callback, element) {
       currTime = new Date().getTime();
       timeToCall = Math.max(0, 16 - (currTime - lastTime));
       lastTime = currTime + timeToCall;
       return window.setTimeout(function() {
           callback(currTime + timeToCall);
         },
         timeToCall);
     };
   }

   if (!window.cancelAnimationFrame) {
     window.cancelAnimationFrame = function(id) {
       clearTimeout(id);
     };
   }
 }());