How does Facebook's Chat Window Remains open and in the same place When you navigate through pages

Question

How does Facebook's Chat Window Remains open and in the same place When you navigate through pages

Please before you answer:

1-I'm aware of Ajax very well and the current implementation in Facebook is not normal Ajax like it used to be in the past.

2-The URL of the page changes completely not the Hash part, and the whole page reloads but not the Chat window or panel.

I Found that the URL changes through this JS Part:

history.pushState({},"New Title Goes Here","http://facebook.com/Something");

But what about the data itself how doesn't it come ? the Network->XHR in Firebug or Chrome displays nothing in the XHR. so I guess it's not Ajax.

Holle

Is it possible that they are storing that box's state in cookie and check this stage on every page? – Spiracle

no the Chat Window doesn't reload doesn't even disappear for 1 milli-second while the whole page reloads as if it was another window just above the page. (But it's not) – Holle

„the Network->XHR in Firebug or Chrome displays nothing in the XHR.” – in my firebug, it sure does. – Dulci

Answer 1

Looks like plenty of ajax to me.

They're selective in when they reload the chat window. Ie: if you go to account settings, and other less-traveled pages.

For the chat window loading itself, I'm fairly certain they use long-polling (comet).

Otisotitis

They use long-polling in everything not only Chat, seems that ever the navigation sometimes goes through the Channel connection (the long polling one). – Holle