HOW TO DO IT， WHEN “onclick="secBoard2(0)” ， THEN PHP request

求教]PHP变量$secmeth怎么获取JS内的secBoard2[n]的值？
HOW TO DO IT， WHEN “onclick="secBoard2(0)” ， THEN PHP request
the value that is secBoard2(n) .
IF USE XMLHTTPREQUEST , HOW TO DO ?


THE CODE:
================================================
<script language=&#106avascript>
function secBoard2(n)
{
for(i=0;i<secTable2.cells.length;i++)
secTable2.cells.className="sec3";
secTable2.cells[n].className="sec4";
for(i=0;i<mainTable2.tBodies.length;i++)
mainTable2.tBodies.style.display="none";
mainTable2.tBodies[n].style.display="block";

<?php $secmeth =
secBoard2[n];//问题的关键点，怎么获取secBoard2[n]的值？?>
}
</script>


<table id="mainTable2">
<tr>
<td onclick="secBoard2(0)">i is 0</td>
<td onclick="secBoard2(1)">i is 1</td>
<td onclick="secBoard2(2)">i is 2</td>
<td onclick="secBoard2(3)">i is 3</td>
</tr>
<tbody>
<tr>
<td>
i is 0
</td>
</tr>
</tbody>
<tbody>
<tr>
<td>
i is 1
</td>
</tr>
</tbody>
<tbody>
<tr>
<td>
i is 2
</td>
</tr>
</tbody>
<tbody>
<tr>
<td>
i is 3
</td>
</tr>
</tbody>
</table>
<?php
echo $secmeth ; //display 0 or 1 or 2 or 3
?>