<!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>