Js弹性漂浮广告代码

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>Js弹性漂浮广告代码</title>
</head>
<body>
<DIV id=img1 style="Z-INDEX: 100; LEFT: 2px; WIDTH: 59px; POSITION: absolute; TOP: 43px; HEIGHT: 61px;
visibility: visible;" onMouseOver="pause_resume()" onMouseOut="pause_resume()"><a href="/" target="_blank"><img src="/jscss/demoimg/201207/pic.gif" width="80" height="80" border="0"></a></DIV>
<SCRIPT language="JavaScript">
var xPos = 300;
var yPos = 200;
var step = 1;
var delay = 5;
var height = 0;
var Hoffset = 0;
var Woffset = 0;
var yon = 0;
var xon = 0;
var pause = true;
var interval;
img1.style.top = yPos;
function changePos()
{
   width = document.body.clientWidth;
   height = document.body.clientHeight;
   Hoffset = img1.offsetHeight;
   Woffset = img1.offsetWidth;
   img1.style.left = xPos + document.body.scrollLeft;
   img1.style.top = yPos + document.body.scrollTop;
   if (yon)
       {yPos = yPos + step;}
   else
       {yPos = yPos - step;}
   if (yPos < 0)
       {yon = 1;yPos = 0;}
   if (yPos >= (height - Hoffset))
       {yon = 0;yPos = (height - Hoffset);}
   if (xon)
       {xPos = xPos + step;}
   else
       {xPos = xPos - step;}
   if (xPos < 0)
       {xon = 1;xPos = 0;}
   if (xPos >= (width - Woffset))
       {xon = 0;xPos = (width - Woffset);   }
   }

   function start()
   {
      img1.visibility = "visible";
       interval = setInterval('changePos()', delay);
   }
   function pause_resume()
   {
       if(pause)
       {
           clearInterval(interval);
           pause = false;}
       else
       {
           interval = setInterval('changePos()',delay);
           pause = true;
           }
       }
   start();
</SCRIPT>
</body>
</html>