用javascript增加表格问题

IE没有报错，说明代码没有问题……没有问题怎么就不出现呢？奇怪了……
偶也新手，很多东西不明白的说～我改写了一点，能够有一点效果了，但是实现不了LZ的要求……<SCRIPT type="text/javaScript">
var index=1;
function addline()
{
//window.alert("aa")
var getTable =document.getElementById("arrTable");
var oTable=document.createElement("table");
oTable.setAttribute("type","oTable");
index++;
var name=oTable+index;
getTable.appendChild(oTable);
var br=document.createElement("br");
getTable.appendChild(br);
window.alert("aa");}
</SCRIPT><div id="arrTable">
<table width="766" height="62" border="1" cellpadding="1" cellspacing="1">
<tr>
<td rowspan="3"> </td>
<td rowspan="3"> </td>
<td rowspan="3"> </td>
<td rowspan="3"> </td>
<td height="20"> </td>
<td height="20"> </td>
<td rowspan="3"> </td>
</tr>
<tr>
<td height="20"> </td>
<td height="20"> </td>
</tr>
<tr>
<td height="20"> </td>
<td height="20"> </td>
</tr>
</table>
</div><p> </p>
<p> </p><input type="button" name="Submit" value="增加" onClick="javascript:addline()">

解决方案 »

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但是这样还是现实不了LZ要求的表格啊！估计问题所在地：
var getTable =document.getElementById("arrTable");
var oTable=document.createElement("table");只有等高手了……
<SCRIPT type="text/javaScript">
var index=1;
function addline()
{
var oTable =document.getElementById("mm").cloneNode(true);
var getDiv   =document.getElementById("mm");
getDiv.appendChild(oTable);
}
</SCRIPT><div id=mm>
<table width="766" height="62" border="1" cellpadding="1" cellspacing="1" ID="Table2">
  <tr>
    <td rowspan="3"> </td>
    <td rowspan="3"> </td>
    <td rowspan="3"> </td>
    <td rowspan="3"> </td>
    <td height="20"> </td>
    <td height="20"> </td>
    <td rowspan="3"> </td>
  </tr>
  <tr>
    <td height="20"> </td>
    <td height="20"> </td>
  </tr>
  <tr>
    <td height="20"> </td>
    <td height="20"> </td>
  </tr>
</table>
<BR>
</div>
<p> </p>
<table width="766" border="1" cellspacing="1" cellpadding="1" ID="Table1">
  <tr>
    <td align="center"><input type="button" name="Submit" value="增  加" onclick="javascript:addline()" ID="Button1"></td>
  </tr>
</table>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
</HEAD><BODY>
<SCRIPT type="text/javaScript">
var index=1;
function addline()
{
var oTable =document.getElementById("mm").cloneNode(true);
var getDiv   =document.getElementById("aaa");
getDiv.appendChild(oTable);
}
</SCRIPT><div id=mm>
<table width="766" height="62" border="1" cellpadding="1" cellspacing="1" ID="Table2">
  <tr>
    <td rowspan="3"> </td>
    <td rowspan="3"> </td>
    <td rowspan="3"> </td>
    <td rowspan="3"> </td>
    <td height="20"> </td>
    <td height="20"> </td>
    <td rowspan="3"> </td>
  </tr>
  <tr>
    <td height="20"> </td>
    <td height="20"> </td>
  </tr>
  <tr>
    <td height="20"> </td>
    <td height="20"> </td>
  </tr>
</table>
<BR>
</div>
<div id="aaa">
</div>
<p> </p>
<table width="766" border="1" cellspacing="1" cellpadding="1" ID="Table1">
  <tr>
    <td align="center"><input type="button" name="Submit" value="add" onclick="javascript:addline()" ID="Button1"></td>
  </tr>
</table></BODY>
</HTML>
高手谈不上，互相学习吧！我的解决思路是这样的，有其他思路的请不吝赐教。
function addline()
{
var oTable =document.getElementById("mm").firstChild.cloneNode(true);
var getDiv   =document.getElementById("mm");
getDiv.appendChild(oTable);
var br=document.createElement("br");
getDiv.appendChild(br);
}