window.requestAnimationFrame = (function() {
    return window.requestAnimationFrame ||
        window.webkitRequestAnimationFrame ||
        window.mozRequestAnimationFrame ||
        window.oRequestAnimationFrame ||
        // if all else fails, use setTimeout
        function(callback) {
            return window.setTimeout(callback, 1000 / 60); // shoot for 60 fps
        };
})();

window.cancelAnimationFrame = (function() {
    return window.cancelAnimationFrame ||
        window.webkitCancelAnimationFrame ||
        window.mozCancelAnimationFrame ||
        window.oCancelAnimationFrame ||
        function(id) {
            window.clearTimeout(id);
        };
})();