Login runtime value from login server behavior?

How do I set up a recordset that will point to the login users' record in PHP once they login from the login server behavior?

In ASP I used the value for the variable actname:       MM_Username.

I just want to link to the username's record.  I thought the "mm_Username" value was something that was created in the login server behavior that came with Dreamweaver and it would work for php as well as asp.

In PHP I am using the following runtime value language :

$_GET['MM_Username']

Is it different in PHP?  It won't point to the record of the login user in the user's account.

How do I set up a recordset so that it will point to the record of the login user if none of this makes sense in php.

Thanks in advance,

Bob Jean