timeline.js

define(function (require, exports, module) {
    var requestAnimationFrame,
	cancelAnimationFrame,
	DEFAULT_INTERVAL = 1000 / 60;

    function Timeline() {

        this.animationHandler = 0;
    }

    Timeline.prototype.onenterframe = function (time) {
        // body...

    };
    Timeline.prototype.start = function (interval) {
        // body...


        var startTime = +new Date(),
		me = this,
		lastTick = 0;
        interval = interval || DEFAULT_INTERVAL;
        //this.onenterframe(new Date - startTime);
        me.stop();
        nextTick();

        function nextTick() {
            var now = +new Date();

            me.animationHandler = requestAnimationFrame(nextTick);

            if (now - lastTick >= interval) {
                me.onenterframe(now - startTime);
                lastTick = now;
            }


        }
    };
    Timeline.prototype.stop = function () {
        // body...
        cancelAnimationFrame(this.animationHandler);
    };

    requestAnimationFrame = (function () {
        return window.requestAnimationFrame ||
            window.webkitRequestAnimationFrame ||
            window.mozRequestAnimationFrame ||
            window.oRequestAnimationFrame ||
        // if all else fails, use setTimeout
            function (callback) {
                return window.setTimeout(callback, 1000 / 60); // shoot for 60 fps
            };
    })();

    // handle multiple browsers for cancelAnimationFrame()
    cancelAnimationFrame = (function () {
        return window.cancelAnimationFrame ||
            window.webkitCancelAnimationFrame ||
            window.mozCancelAnimationFrame ||
            window.oCancelAnimationFrame ||
            function (id) {
                window.clearTimeout(id);
            };
    })();


   module.exports = Timeline;
});