JavaScript实现DIV跟随鼠标移动及多元素拖尾效果

<html>
<head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <title></title>
 <script type="text/javascript">
 window.onload = function () {
  var div1 = document.getElementById('div1');
  document.onmousemove = function (ev) {
  //IE支持event，firefox不支持
  var oEvent = ev || event;
  //
  var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft;
  var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
  div1.style.top = oEvent.clientY + scrollTop + 'px'; //Y
  div1.style.left = oEvent.clientX + scrollLeft + 'px';//X
  };
 };

 </script>
</head>
<body>
 <div id="div1" style="width: 10px; height: 10px; background-color: blue; position: absolute;"></div>
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</body>
</html>

<html>
<head>
 <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
 <title></title>
 <style type="text/css">
 div {
  width: 2px;
  height: 2px;
  background-color: red;
  position: absolute;
 }
 </style>
 <script type="text/javascript">
 window.onload = function () {
  var oDivs = document.getElementsByTagName('div');
  document.onmousemove = function (ev) {
  var oEvent = ev || event;
  document.getElementsByTagName('span')[0].innerHTML = oEvent.clientY + '|' + oEvent.clientX;
  for (var i = oDivs.length-1; i > 0; i--) {
   oDivs[i].style.top = oDivs[i - 1].style.top;
   oDivs[i].style.left = oDivs[i - 1].style.left;
  }
  oDivs[0].style.top = oEvent.clientY+'px';
  oDivs[0].style.left = oEvent.clientX + 'px';
  };

 };
 </script>
</head>
<body>
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</body>
</html>