how to delete session histroy??

[eluser]WanWizard[/eluser]
The only way to prevent a back button to stop working is to tell the browser not to cache the page in the http header. And even that is not fool proof.

I shouldn't focus to much on that. If your application is properly written, any action the user performs on that admin page after using the back button should detect that the user is no longer logged in, and should take appropriate action.