返回顶部在容器的边上,
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8" />
<title> </title>
<meta name="generator" content="editplus" />
<meta name="author" content="" />
<meta name="keywords" content="" />
<meta name="description" content="" />
<style type="text/css">
*{ margin:0; padding:0;}
.body{ width:990px; height:1500px; margin:0 auto; background-color:#d1d1d1;}
.goTop{ width:30px; height:50px; background-color:#f50; position:fixed; bottom:100px; left:50%; margin-left:495px;}/*此margin-left为宽容器的一半*/
.goTop{
_position:absolute;
_bottom:auto;
_top:expression(eval(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-(parseInt(this.currentStyle.marginTop,10)||0)-(parseInt(this.currentStyle.marginBottom,10)||100)));
}
</style>
</head>
<body>
<div class="body"></div>
<div class="goTop"></div>
</body>
</html>
参考新浪微博,方便自己以后使用