Is this for a theme of some sort (like wordpress or similar)? There really is no way you can properly secure code. Its always possible to reverse engineer it, but you can make it fairly hard
you can combine the php with js.......But it's still possible to remove the link.........just make it harder.....
Retain part of the script? on your server, that's if it is a script. Like, supply a footer file with include(' blahblah to your server... which will not only echo your footer link, but also be a part of the main script, some little part, that if removed, nothing will function correctly or display properly
i don't want it to phone home or anything,just make it harder to remove it.i've searched and found nothing. advance users may figure out how to remove it,but a lot of newbies download it. nope,my own script.