I have an upload form, where my form action is something similar to this:
upload.php?zenid=121eajdasdqwdjoiasjoa
Inside the upload.php, I require application_top.php:
require('includes/application_top.php');


And somewhere in the file I use $_SESSION['customer_d']


This works fine when I need use the upload form the normal way. However, when I try to pass the form data to upload.php using Ajax, the SESSION is not available.

Any idea? I'm kinda ajax noob here.