[nikey646]

thanks guys for the replies, well im using a php login system lol, but can you they know the URL of the login page?

Essentially, yes they can, however because php is executed on the server, unless they have access to your server (as in, can edit the login.php) the best they can do is...well nothing unless you make it a functioning site/application combo.

Php is roughly executed in this manor just so you know

User goes to example.com, example.com/index.php is requested by the user, the server (Apache, nginx, Light HTTP, etc) parses code within <?php ?> and shows the output buffer from php (echo, print, printf, etc) to the user.