header('Content-Description: File Transfer');
header('Content-Type: application/vnd.ms-excel');
header('Content-Disposition: attachment; filename="simple.xls"');
header('Content-Transfer-Encoding: binary');
header('Connection: Keep-Alive');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
ob_start();
$writer->save('php://output');
$content = ob_get_contents();
ob_end_clean();
header('Content-Length: ' . strlen($content));
echo $content;