<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<link rel="stylesheet" href="style/main.css">
</head>
<body>
<p id="box"></p>
<br>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br>
<p id="box"></p>
</body>
</html>
<script src="js/jquery-1.11.2.js"></script>
<script src="js/demo.js"></script>
css*{margin: 0;padding: 0;} #box{width: 100px;height: 100px;background: red;position: absolute;right: 0;bottom: 0;}
window.onscroll=function () {
var box=document.getElementById('box');
var scrollTop=document.documentElement.scrollTop||document.body.scrollTop;
box.style.top=document.documentElement.clientHeight-box.offsetHeight+scrollTop+"px";
}
<p id='box'></p>在body里面
为什么不会动而出错了。
