cross browser requestAnimationFrame

requestAnimFrame

window.requestAnimFrame = (function() {
  return window.RequestAnimationFrame   ||
    window.webkitRequestAnimationFrame  ||
    window.mozRequestAnimationFrame     ||
    window.oRequestAnimationFrame       ||
    window.msRequestAnimationFrame      ||
    function(callback) {
      window.setTimeout(callback, 1000/60);
    };
})();