// requestAnimationFrame polyfill thanks to Paul Irish -> http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// And Erik Möller -> http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating
(function() {
	var lastTime = 0;
	var vendors = ['ms', 'moz', 'webkit', 'o'];
	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);
	    };
}());