js缓慢运动，Math.ceil向上取整，floor向下取整 

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
#div1 {width:100px; height:100px; background:red; position:absolute; left:600px; top:50px;}
    #div2 {width:1px; height:300px; background:black; position:absolute; left:300px; top:0}
    </style>
    <script>
    function startMove()
    {
        var oDiv=document.getElementById('div1');
        setInterval(function() {
            var speed=(300-oDiv.offsetLeft)/10;
            //speed=Math.ceil(speed);
            
            speed=speed>0?Math.ceil(speed):Math.floor(speed);
            //在做运动的时候一定不要忘了取整，浏览器会把小数舍弃ceil向上取整floor向下取整
            oDiv.style.left=oDiv.offsetLeft+speed+'px';
            
            
            
            
            document.title=oDiv.offsetLeft ;
        }, 30);
    }
    </script>
</head>

<body>
<input type="button" value="开始运动" onClick="startMove()"/>
<div id="div1">
</div>
<div id="div2"></div>
</body>
</html>

 

posted @ 2020-02-10 15:55  八风不动  阅读(293)  评论(0)    收藏  举报