关于php在iss下导出excel的问题

<?php
header("Content-Type:application/msexcel");
header("Content-disposition:attachment; filename=会员消费清单".date("Ymdhms").".xls");
?>
<?php
include_once("../inc/conn.php");
include_once("../inc/DataPublicFunction.php");
include_once("../inc/PassWord.php");
include_once("../inc/PublicFunction.php");
include_once("../inc/Pager.php");
?>
<table width="790" height="26" border="0" cellpadding="0" cellspacing="0" >
      <tr>
        <td width="26"></td>
        <td align="center" >〖会员消费清单〗</td>
        <td width="16"></td>
      </tr>
    </table>
      <table width="790" border="0" cellpadding="0" cellspacing="0" class="tb02">
        <tr>
为什么不行呢