/*
 * requestAnimationFrame polyfill
 */

(function() {
	var
		lastTime = 0,
		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(),
				timeToCall = Math.max(0, 16 - (currTime - lastTime)),
				id = window.setTimeout( function() { callback(currTime + timeToCall) }, timeToCall )

			lastTime = currTime + timeToCall
			return id
		}
	}

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

}());