Issues while export html table to excel - php

Question

Hi I am going to Export my html form to excel
Here is my code:
<script type="text/javascript">
function callexports()
{
var tabdata=document.getElementById("tabledata").innerHTML;
document.getElementById("tableval").value=tabdata;
document.getElementById("sendtable").submit();
}
</script>
<form id="sendtable" action="exportexcel.php" method="post">
<input type="button" name="Export Excel"
value="Export Excel" onclick="callexports();"/>
<div id="tabledata">
<table border='1'>
<tr >
<th style="background-color:yellow;">Sno</th>
<th style="background-color:yellow;">Name</th>
<th style="background-color:yellow;">Marks</th>
<th style="background-color:yellow;">Age : Age Testing </th>
</tr>
<tr><td>1</td><td>Anvesh</td><td>90</td></tr>
<tr><td>2</td><td>Kapil</td><td>80</td></tr>
<tr><td>3</td><td>Mahesh</td><td>70</td></tr>
<tr><td>4</td><td>Sravan</td><td>90</td></tr>
<tr><td colspan='2'>Total</td><td>330</td></tr>
</table>
</div>
<input type="hidden" name="tableval" id="tableval" />
</form>
**exportexcel.php**
<?php
$filename = "Student_Info".time(); //File Name
$file_ending = "xls";
//header info for browser
header("Content-Type: application/xls");
header("Content-Disposition: attachment; filename=$filename.xls");
header("Pragma: no-cache");
header("Expires: 0");
Echo $_REQUEST['tableval'];
?>
Now it's working fine.But i have a doubt
<th style="background-color:yellow;">Age : Age new Testing </th>
Here Age is My heading and Age new Testing is my description. Is there any way to remove description from <th>. I mean i need only Heading and i want to remove description? Please help me?