README.md

Drop in replace functions for setTimeout and setInterval that make use of requestAnimationFrame.

See overview article and Paul Irish's earlier post.

Courtesty of Joe Lambert

Copyright 2011, Joe Lambert.
Free to use under the MIT license.
http://www.opensource.org/licenses/mit-license.php

More info, resources, and tutorials on web animation best practices here.

requestAnimFrame.js

// requestAnimationFrame() shim by Paul Irish
window.requestAnimFrame = (function() {
	return  window.requestAnimationFrame       || 
		window.webkitRequestAnimationFrame || 
		window.mozRequestAnimationFrame    || 
		window.oRequestAnimationFrame      || 
		window.msRequestAnimationFrame     || 
		function(/* function */ callback, /* DOMElement */ element){
			window.setTimeout(callback, 1000 / 60);
		};
})();

requestInterval.js

/**
 * 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);
};

requestTimeout.js

/**
 * 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);
};