Insert Tables(Urgent)

Hi All,
I have following code in which if I click the button, I want to insert the rows or columns in Table. How this is possible:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>New Page 1</title>
</head>
<SCRIPT LANGUAGE="JavaScript">
function updateValues(){
}
<body>
<table border="1" width="37%">
<tr>
<td width="21%"> </td>
<td width="79%"> </td>
</tr>
<tr>
<td width="21%"> </td>
<td width="79%"> </td>
</tr>
<tr>
<td width="21%"> </td>
<td width="79%"> </td>
</tr>
<tr>
<td width="21%"> </td>
<td width="79%"> </td>
</tr>
<tr>
<td width="21%"> </td>
<td width="79%"> </td>
</tr>
</table>
<p><input type="button" value="Button" name="B3" onClick="updateTable()"></p>
</body>
</html>
Thanks
Angela