carpentry/client/js/libraries/rAF.js

// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

// MIT license

(function () {
	var lastTime = 0;
	var vendors = ['ms', 'moz', 'webkit', 'o'];
	for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
		window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
		window.cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame']
			|| window[vendors[x] + 'CancelRequestAnimationFrame'];
	}

	if (!window.requestAnimationFrame)
		window.requestAnimationFrame = function (callback, element) {
			var currTime = new Date().getTime();
			var timeToCall = Math.max(0, 16 - (currTime - lastTime));
			var id = window.setTimeout(function () { callback(currTime + timeToCall); },
				timeToCall);
			lastTime = currTime + timeToCall;
			return id;
		};

	if (!window.cancelAnimationFrame)
		window.cancelAnimationFrame = function (id) {
			clearTimeout(id);
		};
}());