PHP And jQuery - Chat Security

Question

I have a problem I can't solve.

I have built a chat for an online game, and I want that every page will have a different chat room. The url goes like this = play.php?plc=[arena/advanture/bank/...].

I have a SQL table named pages that defines every page. For instance:

╔════╦══════════════╗
║ id ║  name        ║
╠════╬══════════════╣
║  1 ║ arena        ║
║  2 ║ advanture    ║
║  3 ║ bank         ║
║  4 ║ weapons      ║
╚════╩══════════════╝

Every page do his uniqe calculations, if you're allowed to go in, or you can't. if you can't, I do header(), and exit;.

I'll explain how it's connected to the problem.

How can the ajax file know whether the page was successfuly served, or the permission denied and the exited?

I thought about putting a hidden <input>, but then it'll be hackble. If a user can't go into the page, he can still change the input value to some id, and get access to the page's chat.

Answer 1

The ajax-file can get the param via window.location but you should use a session in php, otherwise users can manipulate this value and read all chats even if they're not there.

session_start();

$_SESSION['area'] = ...;