Gmail's ajax-like system?

[Seregwethrin]

Hello;

Generally ajax doesn't get your page in loading state, but when clicking a link in gmail browser gets into loading state. For example in Firefox site icon became a loading icon and cursor became arrow and sandglass.

How can they do this? Isn't that ajax?

[adni18]

I'm pretty sure they also do something with iframes to ensure that the back button doesn't break.