检查哪个页面叫做这个php？

Here is what I'm dealing with:

Let's say I have some php page:

<?php
    // do php stuff
?>

And I have two HTML pages where the action sends them to this php page. On this php page, I want it to do one thing if it comes from one of the html pages, and something else if it comes from the other. I cannot pass any explicit variables to the php page, I need to check which page called the php.

I have tried:

$_SERVER['PHP_SELF'] when I access this, it doesn't seem the send the referring page. $_SERVER['HTTP_REFERER'] this gives the previous page to the one im looking for.

For example:

HTML PAGE1 form calls php page --> I want some variable in PHP that contains HTML PAGE1. HTML PAGE2 form calls php page --> I want some variable in PHP that contains HTML PAGE2.

Thanks for the help. Please let me know if there's some way I can clarify the question.

If the domain differs you can use:

$_SERVER['SERVER_NAME'];

But in all scenarios this would help:

$_SERVER['REQUEST_URI'];

Giving you the complete URL that was called.

As Think Different said a hidden field in your form is probably your best bet because you don't want to modify the url. In this case you would have the form submit over a POST request and retrive your data with $page = $_POST['YOUR_HIDDEN_VARIABLE_HERE'].