Logout Page

Hi...........
         I'm doing my final year project. In my project if i click "LOGOUT" it directly returns to LOGIN  page.  But  when  i again click the  back button in browser  it returns  to  that  particular page from which i've logged out....
           For that i created a logout page called "invalidate session".......... 
Still i'm getting the same error...........
          Can any one suggest me to overcome this problem...........



Thanks,

Ameen...............