Possible Duplicate:
Securing a remote ajax method call
Is there a way to retrieve the name of the javascript file that called a php script from within the PHP code?
Unfortunately, since I have to call a PHP script from Javascript (for Google maps) on a webpage, this ‘invites’ to retrieve my data by just calling the PHP script by hand. Checking for the script/file that invoked the PHP script would bring at least some protection.
You could set a session variable with some random value on the server when your page is opened, and add that variable in the query string to your php script.
Then in your javascript-called php script, you start the session and check the session variable against the query one.