Server Side operations in a .htm via AJAX

With the recent craze about AJAX, and all the possibilities it can give, there is a subject I have been dying to discuss.

Take for instance a login system, written in PHP. Would it be possible to put that into a .htm file, using AJAX to communicate between Client and Server?

Discuss.

sure your interface might be html files but you need php scripts to process everything

Well, yeh, my thoughts precisley. But how would sessions work?

the html files are only the interface (client code) everything on the serverside need to be processed by php scripts.

it makes no difference if the html code is generated by php or is presented by some html file

No! I mean, have a .htm file with NO php code, and have PHP proccessed by the AJAX

actually that what I said a php file is a html file in the clients browser

Mm i suppose...

I cant see how it would work though. How would you check if the user is logged in?

I don't understand. Why to do this?

A user module is for security. One person can have some personalized features in your site.

If this would be done by javascript alone, anyone would be able to use anyone's rights.

maybe you can tell us first what you try to do, just keeping us busy with your questions is not really fun :)

Sorry :S

Ok... I think ive found a way, thanks :P

Of course there is a way, but I think there is no usability for such a thing. How do you intend to use it?

Well, I was trying to convert a login system into AJAX, but the idea struck me and I decided to try it.