text: (function() {
    var lastTime = 0;
    var vendors = ['webkit', 'moz'];
    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]+'CancelRequestAnimationFrame'];
    }
  
    if (!window.requestAnimationFrame) {
      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);
      };
    }
  }());
  