比较优秀的一款超过一屏高度才显示的，跟随滚动条漂浮的返回顶部按钮特效代码。
<!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>test</title>
<style>
body{ height:2000px;}
.rTop{ width:100px; height:25px; text-align:center; font-size:small; line-height:25px; border:1px solid #999; position:fixed; right:0; bottom:0;
border-bottom-color:#333; border-right-color:#333; margin:5px; cursor:pointer; display:none}
</style>
</head>
<body>
<div class="rTop" id="rTop">返回顶部</div>
<script>
window.οnscrοll=function(){
if(document.body.scrollTop||document.documentElement.scrollTop>0){
document.getElementById('rTop').style.display="block"
}else{
document.getElementById('rTop').style.display="none"
}
}
</script>
</body>
</html>