EveryExercise/requestanimationframe运用.html at master · kitebear/EveryExercise · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="J_num" style="margin: 50px; width: 200px; height: 200px; display: inline-block; background: #ccc"></div>
<div id="J_num2" style="margin: 50px; width: 200px; height: 200px; display: inline-block; background: #ccc"></div>
<script src="http://libs.useso.com/js/jquery/1.9.1/jquery.min.js"></script>
<script>
    // requestAnim shim layer 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);
                };
    })();

    //未优化状态
    (function(){
        var timer;
        var $txt = $('#J_num'),
                num = 0;
        function play(){
            //定时器
            timer = setTimeout(function(){
                stop();
                next();
            },1000)
        }

        function stop(){
            clearTimeout(timer)
        }

        function next(){
            $txt.text(num++);
            play();
        }
        play();
    })();

    //使用raf优化后
    (function(){
        var timer;
        var $txt = $('#J_num2'),
                num = 0;
        function play(){
            //定时器
            timer = setTimeout(function(){
                requestAnimationFrame(function(){
                    stop();
                    next();
                });
            },1000)
        }

        function stop(){
            clearTimeout(timer)
        }

        function next(){
            $txt.text(num++);
            play();
        }
        play();
    })();
</script>
</body>
</html>