title: session is not destroyed
body: <p>i have this file</p>
  
  <p>secure.php
      
  
  <pre><code>session_start();
  if(empty($_SESSION['u_name'])) {
      header("Location:emprego.php");
  }
  
  if(isset($_GET['logout'])) {
      session_destroy();
      header("Location:emprego.php");
  }
  
  $name = $_SESSION['u_name'];
  
  ?&gt;
  
  &lt;li&gt;&lt;?php echo "&lt;a href='emprego.php?logout' id='D'&gt;Logout&lt;/a&gt;";?&gt;&lt;/li&gt;
  </code></pre>
  
  <p>basically, if i do logout, i will be redirected to emprego.php. But if i click in back page button (arrow in browser), i can view the same page (secure.php).</p>
  
  <p>my question is, why?</p>
  
  <p>thanks</p>