This is only an frontend example for yayd.

Change this to your likes.

Outcommented lines are for multiuser support.
To use them you'll need to provide these functions:
hasPerm("perm name") to check if a user has the permission

Setup all files on a webserver.
Change includes/config.ytdownl.db.inc.php to your needs.
Change in js/ytdownl.js DOWNLOAD_LINK to your domain.