title: To understand PHP's header()
body: <p><strong>Where do you use the command header()?</strong></p>
  
  <p>I have the following code at handlers/handle_login.php. The user has gone to the site from <code>index.php</code> which is the starting place.</p>
  
  <pre><code> if(!$logged_in){
       header("Location: index.php");                                                                          
       die("You are not logged_in");
   }
  </code></pre>
  
  <p>If if-clause is true, I get a 404 error, since the header puts me to to <code>handlers/index.php</code>, instead of <code>index.php</code>.</p>