title: prevent back button after logout page
body: <p>I Have php logout page. when user click in logout link See this page and redirect to index page. but when click in back button i see previouse page with user data. of course when i refresh page i dont see previouse page and data. i checked other code ( drupal ) after click logout and click back button i dont see previouse page and see login page. Where is my problem. how to fixed this ? </p>
  
  <p>LOGOUT PAGE : </p>
  
  <pre><code>if (isset($_GET['req']) &amp;&amp; $_GET['req'] == 'logout') {
        session_start();
        session_destroy();
        header("Location: index.php");
     exit();
  }
  </code></pre>
  
  <p>Thanks </p>