求如何将各个组件按要求从上至下显示？
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>nav</title>
<script language="javascript">
startList = function()
{
//if (document.all&&document.getElementById)
//{
var navRoot = document.getElementsByName("qqqq");
alert(navRoot[0].id);
for(j=0;j<navRoot.length;j++)
{
for (i=0; i<navRoot[j].childNodes.length; i++)
{
node = navRoot[j].childNodes[i];
if (node.nodeName=="LI")
{
node.onmouseover=function()
{
this.className+=" over";
}
node.onmouseout=function()
{
this.className=this.className.replace(" over", "");
}
}
}
}
// }
}
window.onload=startList;
<\/script>
<style type="text/css">
body {
font: normal 11px verdana;
}
ul {
margin: 0;
padding: 0;
list-style: none;
width: 70px; /* Width of Menu Items */
border-bottom: 1px solid #ccc;
}
ul li {
position: relative;
}
li ul {
position: absolute;
left: 30px; /* Set 1px less than menu width */
top: 0px;
display: none;
}
/* Styles for Menu Items */
ul li a {
display: block;
text-decoration: none;
color: #777;
background: #fff; /* IE6 Bug */
border: 1px solid #ccc; /* IE6 Bug */
border-bottom: 0;
}
.ullia {
font: normal 11px verdana;
display: block;
text-decoration: none;
color: #777;
background: #fff; /* IE6 Bug */
padding: 3px;
border: 1px solid #ccc; /* IE6 Bug */
border-bottom: 0;
}
.dspone {
z-index: 100;
}
/* Holly Hack. IE Requirement */
* html ul li { float: left; height: 1%; }
* html ul li a { height: 1%; }
/* End */
li:hover ul, li.over ul { display: block; } /* The magic */
</style>
</head>
<body>
<table width="600" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="250" height="20"><div align="left">
<ul id="qqqq">
<li ><label class="ullia">功能XXXXXXXX</label>
<ul class="dspone">
<li><a class="ullia" href="">编辑</a></li>
<li><a class="ullia" href="">删除</a></li>
<li><a class="ullia" href="">打印/导出</a></li>
</ul>
</li>
</ul>
</div></td>
<td width="150" height="20"><div align="left"></div></td>
<td width="200" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="50" height="20"></td>
<td width="450" height="20"><div align="left"></div></td>
<td width="100" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
</table>
<table width="600" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="250" height="20"><div align="left">
<ul id="qqqq">
<li ><label class="ullia">功能........</label>
<ul >
<li><a class="ullia" href="">编辑</a></li>
<li><a class="ullia" href="">删除</a></li>
<li><a class="ullia" href="">打印/导出</a></li>
</ul>
</li>
</ul>
</div></td>
<td width="150" height="20"><div align="left"></div></td>
<td width="200" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="50" height="20"></td>
<td width="450" height="20"><div align="left"></div></td>
<td width="100" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
</table>
<table width="600" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="250" height="20"><div align="left">
<ul id="qqqq">
<li ><label class="ullia">功能........</label>
<ul >
<li><a class="ullia" href="">编辑</a></li>
<li><a class="ullia" href="">删除</a></li>
<li><a class="ullia" href="">打印/导出</a></li>
</ul>
</li>
</ul>
</div></td>
<td width="150" height="20"><div align="left"></div></td>
<td width="200" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="50" height="20"></td>
<td width="450" height="20"><div align="left"></div></td>
<td width="100" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
</table>
<table width="600" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="250" height="20"><div align="left">
<ul id="qqqq">
<li ><label class="ullia">功能........</label>
<ul >
<li><a class="ullia" href="">编辑</a></li>
<li><a class="ullia" href="">删除</a></li>
<li><a class="ullia" href="">打印/导出</a></li>
</ul>
</li>
</ul>
</div></td>
<td width="150" height="20"><div align="left"></div></td>
<td width="200" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
<tr>
<td width="600" height="20"><table width="600" height="20" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="50" height="20"></td>
<td width="450" height="20"><div align="left"></div></td>
<td width="100" height="20"><div align="left"></div></td>
</tr>
</table></td>
</tr>
</table>
</body>
</html> ;
这样弹出来的会被下一行挡着，怎样将弹出来的菜单不被任何组件挡即显示在最前面
