<script type="text/javascript">var k = 1;</script>      
   <table>  

</table>

<script type="text/javascript">      
   if (k==1) {document.write('<tr>')}      
   k = k+1;      
   if (k>3) k -= 3;      
   </script>      
   <td>  

</td>      
   <script type="text/javascript">      
   if (k==3) document.write('</tr>');      
   </script>