// requestAnimationFrame() shim by Paul Irish
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
window.requestAnimFrame = (function() {
	return  window.requestAnimationFrame       ||
		window.webkitRequestAnimationFrame ||
		window.mozRequestAnimationFrame    ||
		window.oRequestAnimationFrame      ||
		window.msRequestAnimationFrame     ||
		function(/* function */ callback, /* DOMElement */ element){
			window.setTimeout(callback, 1000 / 60);
		};
})();

/**
 * Behaves the same as setInterval except uses requestAnimationFrame() where possible for better performance
 * @param {function} fn The callback function
 * @param {int} delay The delay in milliseconds
 */
window.requestInterval = function(fn, delay) {
	if( !window.requestAnimationFrame       &&
		!window.webkitRequestAnimationFrame &&
		!(window.mozRequestAnimationFrame && window.mozCancelRequestAnimationFrame) && // Firefox 5 ships without cancel support
		!window.oRequestAnimationFrame      &&
		!window.msRequestAnimationFrame)
		return window.setInterval(fn, delay);

	var start = new Date().getTime(),
		handle = new Object();

	function loop() {
		var current = new Date().getTime(),
			delta = current - start;

		if(delta >= delay) {
			fn.call();
			start = new Date().getTime();
		}

		handle.value = requestAnimFrame(loop);
	};

	handle.value = requestAnimFrame(loop);
	return handle;
}

/**
 * Behaves the same as clearInterval except uses cancelRequestAnimationFrame() where possible for better performance
 * @param {int|object} fn The callback function
 */
window.clearRequestInterval = function(handle) {
	window.cancelAnimationFrame ? window.cancelAnimationFrame(handle.value) :
		window.webkitCancelAnimationFrame ? window.webkitCancelAnimationFrame(handle.value) :
			window.webkitCancelRequestAnimationFrame ? window.webkitCancelRequestAnimationFrame(handle.value) : /* Support for legacy API */
				window.mozCancelRequestAnimationFrame ? window.mozCancelRequestAnimationFrame(handle.value) :
					window.oCancelRequestAnimationFrame	? window.oCancelRequestAnimationFrame(handle.value) :
						window.msCancelRequestAnimationFrame ? window.msCancelRequestAnimationFrame(handle.value) :
							clearInterval(handle);
};

/**
 * Behaves the same as setTimeout except uses requestAnimationFrame() where possible for better performance
 * @param {function} fn The callback function
 * @param {int} delay The delay in milliseconds
 */

window.requestTimeout = function(fn, delay) {
	if( !window.requestAnimationFrame      	&&
		!window.webkitRequestAnimationFrame &&
		!(window.mozRequestAnimationFrame && window.mozCancelRequestAnimationFrame) && // Firefox 5 ships without cancel support
		!window.oRequestAnimationFrame      &&
		!window.msRequestAnimationFrame)
		return window.setTimeout(fn, delay);

	var start = new Date().getTime(),
		handle = new Object();

	function loop(){
		var current = new Date().getTime(),
			delta = current - start;

		delta >= delay ? fn.call() : handle.value = requestAnimFrame(loop);
	};

	handle.value = requestAnimFrame(loop);
	return handle;
};

/**
 * Behaves the same as clearTimeout except uses cancelRequestAnimationFrame() where possible for better performance
 * @param {int|object} fn The callback function
 */
window.clearRequestTimeout = function(handle) {
	window.cancelAnimationFrame ? window.cancelAnimationFrame(handle.value) :
		window.webkitCancelAnimationFrame ? window.webkitCancelAnimationFrame(handle.value) :
			window.webkitCancelRequestAnimationFrame ? window.webkitCancelRequestAnimationFrame(handle.value) : /* Support for legacy API */
				window.mozCancelRequestAnimationFrame ? window.mozCancelRequestAnimationFrame(handle.value) :
					window.oCancelRequestAnimationFrame	? window.oCancelRequestAnimationFrame(handle.value) :
						window.msCancelRequestAnimationFrame ? window.msCancelRequestAnimationFrame(handle.value) :
							clearTimeout(handle);
};