PHPExcel generate htm instead of xls -

i need generate xls files using phpexcel class, have problem extention:

header('content-type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'); header('content-disposition: attachment;filename="file.xls"'); header('cache-control: max-age=0'); ... $objwriter = phpexcel_iofactory::createwriter($objphpexcel, 'excel5'); $objwriter->save('php://output'); exit; 

using code browser wants download file.xls.htm file insetead of file.xls ... why ? version of phpexcel have used 1.7.8, 2012-10-12

make sure don't have white spaces or "empty" echo's in *.php