AJAX NT Authentication gotcha
Ran into this recently, thought I'd pass it on...
basically, AJAX using POST in an nt authenticated environment doesn't work. You get a popup box for nt usename/password but all it ever does it keep coming up. It's like AJAX post requests don't care NT auth info or something.
GET, however, works.
Also, it's possible to have firefox automatically nt authenticate rather than having to do it manually via a prompt. Of limited use but may be handy in some cases. You have to manually allow each host. Instructions here:
http://www.security-forums.com/viewtopic.php?t=33159
basically you have to tweak about:config values