关于在javascript中,定位层的问题

下面代码中,我要把层定位在单元格"d1"的位置?但程序没得反映得,结果层还是显示在表格最下面.为什么.要如何定位层呢?
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
    <link href="../Include/Style/Style.css" type="text/css" rel="stylesheet">
    <script type="text/javascript">
    function showpan()
{
var x=document.getElementById("d1").style.left;
var y=document.getElementById("d1").style.top;

document.getElementById("univlist").style.left =x;
document.getElementById("univlist").style.top = y;

document.getElementById("univlist").style.display = "block";
}
    </script>
</head>
<body>
    <form id="form1" runat="server">           
<table cellspacing="0" cellpadding="0" width="100%" border="1">
<tr>
<td height="60">&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td id="d1"><input type="text" id="tb" onclick="showpan()"/></td>
</tr>
<tr>
    <td style="height:100px" colspan="2">&nbsp;</td>
</tr>
</table>
<DIV id="univlist" style="position:relative;z-index:30;display:none;">
          <LI class="active" id="c_0"><A 
          href="http://reg.xiaonei.com/register.do#">中国</A> </LI>
          <LI id="c_7"><A o
          href="http://reg.xiaonei.com/register.do#">美国</A> </LI>
          <LI id="c_6"><A
          href="http://reg.xiaonei.com/register.do#">加拿大</A> </LI>
          <LI id="c_5"><A
          href="http://reg.xiaonei.com/register.do#">英国</A> </LI>
          <LI id="c_1"><A 
          href="http://reg.xiaonei.com/register.do#">澳大利亚</A> </LI>
          <LI id="c_2"><A 
          href="http://reg.xiaonei.com/register.do#">法国</A> </LI>
          <LI id="c_8"><A 
          href="http://reg.xiaonei.com/register.do#">德国</A> </LI>
          <LI id="c_4"><A
          href="http://reg.xiaonei.com/register.do#">新西兰</A> </LI>
          <LI id="c_3"><A 
          href="http://reg.xiaonei.com/register.do#">新加坡</A> </LI></UL>
        </DIV>
    </form>
</body>
</html>

解决方案 »

  1.   

    <DIV   id="univlist"   style="position:absolute;z-index:30;display:none;"> 
                        <LI   class="active"   id="c_0"> <A   
                        href="http://reg.xiaonei.com/register.do#"> 中国 </A>   </LI> 
                        <LI   id="c_7"> <A   o 
                        href="http://reg.xiaonei.com/register.do#"> 美国 </A>   </LI> 
                        <LI   id="c_6"> <A 
                        href="http://reg.xiaonei.com/register.do#"> 加拿大 </A>   </LI> 
                        <LI   id="c_5"> <A 
                        href="http://reg.xiaonei.com/register.do#"> 英国 </A>   </LI> 
                        <LI   id="c_1"> <A   
                        href="http://reg.xiaonei.com/register.do#"> 澳大利亚 </A>   </LI> 
                        <LI   id="c_2"> <A   
                        href="http://reg.xiaonei.com/register.do#"> 法国 </A>   </LI> 
                        <LI   id="c_8"> <A   
                        href="http://reg.xiaonei.com/register.do#"> 德国 </A>   </LI> 
                        <LI   id="c_4"> <A 
                        href="http://reg.xiaonei.com/register.do#"> 新西兰 </A>   </LI> 
                        <LI   id="c_3"> <A   
                        href="http://reg.xiaonei.com/register.do#"> 新加坡 </A>   </LI> </UL> 
                    </DIV> 
      

  2.   

    style="position:relative;z-index:30;display:none;"> 
    改为绝对定位position:absolute;