How are the facebook chat windows implemented?

Question

On Facebook you can browse the site without affecting the floating chat windows. Seems like if the main page was inside an iFrame and the footer and chat windows where float

Answer 1

It's an absolutely positioned div, positioned at the bottom of your browser window. It's not hard, I cloned the Facebook chat for ClockingIT from scratch in a weekend.

Answer 2

Probobly just an absolutely positioned div, containing a scrolling div for the content. Ajax would provide the content.

Answer 3

If you install FireBug and enable the net monitor for Facebook, you'll see that when you click most links inside the application, you're not doing a full page refresh, but rather an AJAX call which updates the page with the new content.

It looks like a new page, but in reality you're on the same page with just about everything but the chat-bar replaced.

Answer 4

The chat windows do indeed refresh when you load a new page, they maintain their viewstate however (open/close/chat history).