Closing Sessions

[eluser]ninjayan[/eluser]
Hi everyone! It's me again.

Currently, I have this logout function

Code:

public function logout() {
  $this->session->sess_destroy();
  redirect('main/index');
}

and this is the logout link

Code:

echo "<li class='left'>".anchor(base_url('site/logout'), 'Logout')."</li>";

It goes to logout function and redirect to index.
Problem: But when I try to click the back button, the session is still there
Help.

[eluser]skunkbad[/eluser]
Apply no-cache headers. Search on Google or see MY_Controller of Community Auth.