php - Communicating between an overlayed iFrame and the underlying page (LAMP) -

I have a small form that I have to fill.

If the user is logged in, the form is presented in normal form if the user is not logged in, then I show an overlayer with an iframe page which contains a login box where He enters his credentials if the credentials are correct, then I can "break out" the frame to "return" to the main page, but how can I update this main page For example, "Now you are logged in" and JS / PHP login determines whether the form can be presented normally and can not be repeated again from overlayer prompts?

Afack, these two separate pages do not know about each other, so I'm struggling to solve a solution.

This is in a LAMP / jQuery / CodeIgniter environment.

EDIT: Can CodeIgniter XML RPC class be useful for this?

probably do not use the best one iframe and only use AJX

It is very difficult to communicate with an iframe.