var layers=new Array("Layer1","Layer2","Layer3","Layer4","Layer5","Layer6")//将层id写到该数组
function delalllayer(ids)//清除所有层
{
for(i=0;i<ids.length;i++)
eval("document.all."+ids[i]+".style.visibility='hidden'")
}
function layerattribshow(ids)//显示指定层
{
eval("document.all."+ids+".style.visibility='visible'")
}
function layerattribhidden(ids)//隐藏指定层
{
eval("document.all."+ids+".style.visibility='hidden'")
}
/*
<table><tr><td onMouseOver="delalllayer(layers);layerattribshow('Layer1')">test</td></tr></table>
<div id="Layer1" style="position:absolute; z-index:1; left: 10px; top: 39px; visibility: hidden; width: 530px; height: 32px;"> 
<div id="Layer1" style="position:absolute; z-index:3; left: 87px; top: 39px; visibility: hidden;"> 
  <table border=0 onMouseOver="layerattribshow('Layer3')" onMouseOut="layerattribhidden('Layer3')" bgcolor=Coral><tr><td><a href='http://www.srm.cn/dian/index.html' class='a2' target=_blank>电度表厂有限公司</a></td></tr></table></div>
*/