[PHP] pobierz, plaintext 
<?php
<form action="?strona=zmienna" method="post">
?>
[PHP] pobierz, plaintext 

[PHP] pobierz, plaintext 
<?php
<form action="ht://strona.pl/?strona=zmienna" method="post">
?>
[PHP] pobierz, plaintext 

[PHP] pobierz, plaintext 
<?php
<form action="'.$_SERVER['SERVER_NAME'].'?strona=zmienna" method="post">
?>
[PHP] pobierz, plaintext 

[PHP] pobierz, plaintext 
<?php
<form action="'.$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'].'" method="post">
?>
[PHP] pobierz, plaintext