This is a sandbox to test the requestAnimationFrame Polyfill as offered by http://www.calormen.com/polyfill/. Mainly targeting Webkit 533.1 in order to gain some form of rendering framerate control on android 2 devices.

requestAnimationFrame Polyfill (by calormen)

// requestAnimationFrame
// http://www.w3.org/TR/animation-timing/
(function() {
	var TARGET_FPS = 60,
		requests = {},
		raf_handle = 1,
		timeout_handle = -1;

	function isVisible(element) {
		return element.offsetWidth > 0 && element.offsetHeight > 0;
	}

	function onFrameTimer() {
		var cur_requests = requests, id, request;

		requests = Object.create(null);
		timeout_handle = -1;

		for (id in cur_requests) {
			if (Object.prototype.hasOwnProperty.call(cur_requests, id)) {
				request = cur_requests[id];
				if (!request.element || isVisible(request.element)) {
					request.callback(Date.now());
				}
			}
		}
	}

	function requestAnimationFrame(callback, element) {
		var cb_handle = raf_handle++;
		requests[cb_handle] = {callback: callback, element: element};

		if (timeout_handle === -1) {
			timeout_handle = window.setTimeout(onFrameTimer, 1000 / TARGET_FPS);
		}

		return cb_handle;
	}

	function cancelAnimationFrame(handle) {
		delete requests[handle];

		if (Object.keys(requests).length === 0) {
			window.clearTimeout(timeout_handle);
			timeout_handle = -1;
		}
	}

	window.requestAnimationFrame =
		window.requestAnimationFrame ||
		window.webkitRequestAnimationFrame ||
		window.mozRequestAnimationFrame ||
		window.oRequestAnimationFrame ||
		window.msRequestAnimationFrame ||
		requestAnimationFrame;

	// NOTE: Older versions of the spec called this "cancelRequestAnimationFrame"
	window.cancelAnimationFrame = window.cancelRequestAnimationFrame =
		window.cancelAnimationFrame || window.cancelRequestAnimationFrame ||
		window.webkitCancelAnimationFrame || window.webkitCancelRequestAnimationFrame ||
		window.mozCancelAnimationFrame || window.mozCancelRequestAnimationFrame ||
		window.oCancelAnimationFrame || window.oCancelRequestAnimationFrame ||
		window.msCancelAnimationFrame || window.msCancelRequestAnimationFrame ||
		cancelAnimationFrame;
}());