don't click the back-arrow button. The behavior for it is _very_ different from one browser to the next, and most often you won't get _any_ indication on the server side that it's been done. Plus your control over what happens when the back button is pressed is extremely limited.
Give users plenty of navigation options - and if they ask tell them not to press that button.
If you like start your app in an "empty" browser window which does not have those controls, or an address bar etc.
cheers
Bruce