request animation

gistfile1.js

var requestAnimFrame = (function () {
    return  window.requestAnimationFrame ||
        window.webkitRequestAnimationFrame ||
        window.mozRequestAnimationFrame ||
        window.oRequestAnimationFrame ||
        window.msRequestAnimationFrame ||
        function (/* function */ callback, /* DOMElement */ element) {
            window.setTimeout( callback, 16.667 );
        };
})();