when i click back or forward button wont display direcly on pages .it ll ask login page .after i logout

Question

In my application login form and detail form . In detail from contains report grid and logout button.
In logout button i have written   Session.Abandon(); then it redirects to login form .But if
i click back button it goes to detail page . how to avoid this ? this should display only login page.


 when i click back or forward button after logout.i want to display login page.


Thanks&regards
  Venkat.S