<?php
header('Content-type: application/excel');
$filename = 'filename.xls';
header('Content-Disposition: attachment; filename='.$filename);
$data = '<html xmlns:x="urn:schemas-microsoft-com:office:excel">
<head>
<title>Page Title</title>
</head>
<body>
<table><tr><td>Cell 1</td><td>Cell 2</td></tr></table>
</body></html>';
echo $data;
?>