javascript内部弹窗问题急

Question

各位javascript高手们，请看下面代码:
我想将弹出来的内部窗口在网页中居中:
请各位高手位帮忙处理:
<table border="0" cellpadding="0" cellspacing="0" width="100%" height="38" >
  <tr> 
    <td valign="top" height="40"><fieldset><legend>数据管理</legend> 
      <table width="100%" border="0">
        <tr> 
          <td width="97%"> 
            <table border="1" height="32" cellspacing="0" cellpadding="2" align="center" bordercolordark="#FFFFFF" bordercolor="888888" width="98%">
              
              <tr>
  
                <td height="25">
                      
                  <div id="Layer10" style="position:absolute; width:300px; height:20px;z-index:1; top:0px; left: 0px; visibility: hidden;margin-left: auto; margin-right: auto;"> 
                    
<table width="100%" border="0" height="100%" bgcolor="#666666" cellspacing="1" cellpadding="0">
                      <tr>
                            <td bgcolor="#FFFFCC"> 
                                <table width="100%" border="0">
                                  <tr>
                                    <td valign="top" align="right">
                                      <img src="Images/close.gif" width="13" height="11" border="0" onclick="javascript:document.all.Layer10.style.visibility='hidden';"> 
                                    </td>
                                  </tr>
                                  <tr>
                                    <td>
                                      <div>fdsafaff</div>
                                    </td>
                                  </tr>
                                </table>
                              </div>
                            </td>
                      </tr>
                    </table>
                  </div>
                   <script language=javascript>
   function LayerFun(str){
if(document.all['Layer'+str].style.visibility="hidden"){
document.all['Layer'+str].style.visibility="visible";
}
else{
document.all['Layer'+str].style.visibility="hidden";
}
   }
   </script>
                   <a href="#" onclick="LayerFun(10);">奶奶的</a> </td>
              </tr>
      </table>
</table>

Answer 1

<table border="0" cellpadding="0" cellspacing="0" width="100%" height="38" >
  <tr> 
    <td valign="top" height="40"><fieldset><legend>数据管理</legend> 
      <table width="100%" border="0">
        <tr> 
          <td width="97%"> 
            <table border="1" height="32" cellspacing="0" cellpadding="2" align="center" bordercolordark="#FFFFFF" bordercolor="888888" width="98%">
              
              <tr>
  
                <td height="25">
                      
                  <div id="Layer10" style="position:absolute; width:300px; height:20px;z-index:1; top:0px; left: 0px; visibility: hidden;margin-left: auto; margin-right: auto;"> 
                    
<table width="100%" border="0" height="100%" bgcolor="#666666" cellspacing="1" cellpadding="0">
                      <tr>
                            <td bgcolor="#FFFFCC"> 
                                <table width="100%" border="0">
                                  <tr>
                                    <td valign="top" align="right">
                                      <img src="Images/close.gif" width="13" height="11" border="0" onclick="javascript:document.all.Layer10.style.visibility='hidden';"> 
                                    </td>
                                  </tr>
                                  <tr>
                                    <td>
                                      <div>fdsafaff</div>
                                    </td>
                                  </tr>
                                </table>
                              </div>
                            </td>
                      </tr>
                    </table>
                  </div>
                   <script language=javascript>
   function LayerFun(str){
if(document.all['Layer'+str].style.visibility="hidden"){
document.all['Layer'+str].style.visibility="visible";
document.all['Layer'+str].style.left=document.body.clientWidth/2-150;
document.all['Layer'+str].style.top=document.body.clientHeight/2-50;
}
else{
document.all['Layer'+str].style.visibility="hidden";
}
   }
   </script>
                   <a href="#" onclick="LayerFun(10);">奶奶的</a> </td>
              </tr>
      </table>
</table>