Session Reset when clicking back button of the browser

hi friends...
here is my query....
kindly give ur views pls...
after logging into the application,i redirect to company list
when user clicks the browser back button it should show the login
page.that is i want to destroy the in my login controller i
have written code below.
def log_in
  if request.get?

in my routes.rb
map.root :controller => "login",:action => "log_in"
but when i click browser back button it shows login page but it doesnot
go to the log_in action.
Any helps ....
Thanks a bunch

I think that that will be a function of the browser. Some browsers reload the page on back button, so just display content from the cache. Either way, unless you can specify to not cache the page, and the browser honours it, not much you can do to stop it happening.