(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) {

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);

};

}

}());