Passing variable via POST without forms

[bj_]

I have a script that runs on all my pages. It needs to know what the previous page was if there was one. Is there a way to pass the the url via post without using a form? I don't want to pass it by attaching it to the url of all my links. Also, I don't want to write a javascript.

I have a login script that only sets variables after the page went through once. I get warnings that my index was not set ( $POST['INDEX'] ). Is it good code to initalize those indexes before hand.
for example: ( this is the form of my script )
( my regestration is about the same except it
has like 10 $POST variables at it gets ugly if
I do it like this )

if ( !isset( $POST('USER_NAME') ) {
$POST['USER_NAME'] = "";
}

if ( !isset( $POST('PASSW') ) {
$POST['PASSW'] = "";
}

$logged_in = 0;

if ( $POST['USER_NAME'] != "" && $POST['PASSW'] != "" ) {
//validate...
//login...
$logged_in = 1;
//echo out confermation
//echo out link to return to page before login
}

if ( !$logged_in ) {
// echo out login form
}

[matt_4013]

http://www.azmoo.net/index.php?page=3&tut_id=1

[trex005]

If I'm corrrect about whay you are asking you are looking for the refering pages URL
check out HTTP_REFERER at the following link. a note is, you may not want to use this for enterprise level security, but if it is for a functionality boost it can be incredibly nice

http://us3.php.net/manual/en/reserved.variables.php#reserved.variables.server