There is no way to disable the back button -- about all we have are work
arounds. My favorite is putting a javscript "history.go(1)" in the body's
onload event.
I agree, at first, I was of the opinion, that it's too controlling, and bad
application design if you have to block browser features.
Then I realized, users are stupid. They will do everything you never thought
they would
careful where you put them though, I don't think there is anything more
irritating that doing a google search, following a result only to not be
allowed to get back to the google page cause of some client side block
script. Errr.. get's me mad just thinking about it...