<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
</head>
<body>
<style>
#goTopBtn {
position: fixed;
line-height:36px;
width:36px;
bottom:35px;
right:235px;
height:36px;
cursor:pointer;
display:block;
color:red;
font-size:40px;
}
</style>
<br/>
<p style="text-align:center;font-family:Georgia, ‘Times New Roman‘, Times, serif;font-size:24px;font-weight:bold;"></p>
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<div id="goTopBtn">1321687461321</div>
<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.js"></script>
<!--<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script>-->
<script type="text/javascript">
//返回顶部
$(document).ready(function(){
$(window).scroll(function(){
var sc=$(window).scrollTop();
var rwidth=$(window).width()
if(sc>0){
$("#goTopBtn").css("display","block");
// $("#goTopBtn").css("left",(rwidth-36)+"px")
}else{
$("#goTopBtn").css("display","none");
}
})
$("#goTopBtn").click(function(){
var sc=$(window).scrollTop();
$(‘body,html‘).animate({scrollTop:0},500);
})
})
</script>
</body>
</html>
原文：http://www.cnblogs.com/-CLAY-/p/gotop.html