缓速动画原理 

<!DOCTYLE html>
<html>
<head>
    <meta charset="uft-8" />
    <style>
        #box {width:100px; height: 100px; background:#dfd; position:absolute; left:100px; top:100px;}
    </style>
</head>
<body>
<button id="btn">600</button>
<div id="box"></div>
</body>
</html>
<script>
    var btn = document.getElementById('btn');
    var box = document.getElementById('box');
    var target = 600;
    var step = 0;
    var timer = null;
    btn.onclick = function () {
        timer = setInterval(function () {
            step =(target - box.offsetLeft)/10;//要放到定时器里面 
            step = step > 0 ? Math.ceil(step) : Math.floor(step);
            box.style.left = box.offsetLeft+ step +'px';
            if(box.offsetLeft>= target) {
                clearInterval(timer)
            }
            console.log(box.offsetLeft)
        },40)
    }
</script>

 

posted @ 2016-12-24 11:55  ifIhaveWings  阅读(190)  评论(0)    收藏  举报