请教问题~马上给分

脚本说明:
第一步:把如下代码加入<head>区域中
<SCRIPT language=javascript><!--
function out()
{
if(window.event.toElement.id!="menu"        &&       window.event.toElement.id!="link")
  menu.style.visibility="hidden";
}
//-->function out1()
{
if(window.event.toElement.id!="menu1"        &&       window.event.toElement.id!="link")
  menu1.style.visibility="hidden";
}
//-->
</SCRIPT>第二步:把如下代码加入<body>区域中
<div id="back" onmouseout="out()"style="position:absolute;top:180;left:310;width:160;height:40;z-index:1;visibility:visible;">
<span id="menubar"  onmouseover="menu.style.visibility='visible'">
<font  color=red size=2>菜单</span>
<div border=1  id="menu" style="position:absolute;top:15;left:0;width:50;height:10;z-index:2;visibility:hidden;">
<a id="link" href="rjxz.htm">软件下载</a>
<a id="link" href="yxxz.htm">游戏下载</a>
<a id="link" href="hjsj.htm">黄金书籍</a>
<a id="link" href="mntk.htm">美女图库</a>
<a id="link" href="mp3.htm">MP3金曲</a>
<a id="link" href="flash.htm">FLASH</a>
</div>
</div>
<div id="back" onmouseout="out1()"style="position:absolute;top:180;left:370;width:160;height:40;z-index:3;visibility:visible;">
<span id="menubar"  onmouseover="menu1.style.visibility='visible'">
<font  color=red size=2>菜单</span>
<div border=1  id="menu1" style="position:absolute;top:15;left:0;width:50;height:10;z-index:4;visibility:hidden;">
<a id="link" href="rjxz.htm">软件下载</a>
<a id="link" href="yxxz.htm">游戏下载</a>
<a id="link" href="hjsj.htm">黄金书籍</a>
<a id="link" href="mntk.htm">美女图库</a>
<a id="link" href="mp3.htm">MP3金曲</a>
<a id="link" href="flash.htm">FLASH</a>
</div>
</div>