 <p>See <a href="http://www.w3schools.com/media/media_mimeref.asp" rel="nofollow noreferrer">http://www.w3schools.com/media/media_mimeref.asp</a> .</p> <p>xls is <code>application/vnd.ms-excel</code>, ppt is <code>application/vnd.ms-powerpoint</code>.</p>