<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>无标题文档</title>
<style>
body{margin:0; padding:0}
#to_top{width:30px; height:40px; padding:20px; font:14px/20px arial; text-align:center; background:#06c; position:absolute; cursor:pointer; color:#fff}
</style>
<script>
window.onload = function(){
var oTop = document.getElementById("to_top");
document.onmousemove = function(evt){
var oEvent = evt || window.event;
var scrollleft = document.documentElement.scrollLeft || document.body.scrollLeft;
var scrolltop = document.documentElement.scrollTop || document.body.scrollTop;
oTop.style.left = oEvent.clientX + scrollleft +10 +"px";
oTop.style.top = oEvent.clientY + scrolltop + 10 + "px";
}
}
</script>
</head>
<body style="height:1000px;">
<div id="to_top">鼠标跟随</div><!--跟随鼠标的div，一定要设置position，并且position一定是absolute-->
</body>
</html>
