1
(function() {
2
  var lastTime = 0;
3
  var vendors = ['webkit', 'moz'];
4
  for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
5
    window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
6
    window.cancelAnimationFrame =
7
    window[vendors[x]+'CancelAnimationFrame'] || window[vendors[x]+'CancelRequestAnimationFrame'];
8
  }
9

10
  if (!window.requestAnimationFrame) {
11
    window.requestAnimationFrame = function(callback, element) {
12
      var currTime = new Date().getTime();
13
      var timeToCall = Math.max(0, 16 - (currTime - lastTime));
14
      var id = window.setTimeout(function() { callback(currTime + timeToCall); },
15
      timeToCall);
16
      lastTime = currTime + timeToCall;
17
      return id;
18
    };
19
  }
20

21
  if (!window.cancelAnimationFrame) {
22
    window.cancelAnimationFrame = function(id) {
23
      clearTimeout(id);
24
    };
25
  }
26
}());
27

28