(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);

            };

}());