How Gmail makes IE Back work without refresh?

Question

Gmail uses # when you click on a mail to distinguish the page (+ Ajax action). http://mail.google.com/mail/#inbox/1238e709e37a1394

I found: Google using # instead of sea

Answer 1

This is what I was looking for: http://nix.lv/history/demo.html#3

Found it on: Save the anchor in the ie6 history