xiuli.gao
/
bigData


			
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							<!doctype html>
<html lang="en">
<head>
    <title>Document</title>
    <style>
        #e{
            width: 100px;
            height: 100px;
            background: red;
            position: absolute;
            left: 0;
            top: 0;
            zoom: 1;
        }
    </style>
</head>
<body>
<div id="e"></div>
<script>


    var e = document.getElementById("e");
    var flag = true;
    var left = 0;
    //当前执行时间
    var nowTime = 0;
    //记录每次动画执行结束的时间
    var lastTime = Date.now();
    //我们自己定义的动画时间差值
    var diffTime = 40;

    function render() {
        if(flag == true){
            if(left>=100){
                flag = false
            }
            e.style.left = ` ${left++}px`
        }else{
            if(left<=0){
                flag = true
            }
            e.style.left = ` ${left--}px`
        }
    }

    //requestAnimationFrame效果
    (function animloop() {
        //记录当前时间
        nowTime = Date.now()
        // 当前时间-上次执行时间如果大于diffTime，那么执行动画，并更新上次执行时间
        if(nowTime-lastTime > diffTime){
            lastTime = nowTime
            render();
        }
        requestAnimationFrame(animloop);

    })()
</script>
</body>
</html>