rAF shim

gistfile1.txt

window.requestAnimFrame = (function(global) {
  var callbackList = [],
      timer,
      nextTimeSlot = 0;

  function processCallbacks () {
    var localCBList = callbackList,
        now = +(new Date), cb;

    callbackList = [];
    timer = null;
    nextTimeSlot = now + 17; // ~59 fps

    while (cb = localCBList.shift()) {
      cb(now);
    }
  }

  function universalRAFShim (callback) {
    callbackList.unshift(callback);

    if (!timer) {
      timer = global.setTimeout(processCallbacks, Math.max(nextTimeSlot - (new Date), 0));
    }
  }

  return  global.requestAnimationFrame || 
          global.webkitRequestAnimationFrame || 
          global.mozRequestAnimationFrame || 
          global.oRequestAnimationFrame || 
          global.msRequestAnimationFrame ||
          universalRAFShim;
})(window);