title: Force Cache-Control: no-cache in Chrome via XMLHttpRequest on F5 reload
body: <p>I want to ensure that data I request via an AJAX call is fresh and not cached. Therefor I send the header <code>Cache-Control: no-cache</code></p>
  
  <p>But my Chrome Version 33 overrides this header with <code>Cache-Control: max-age=0</code> if the user presses F5.</p>
  
  <p>Example. Put a <code>test.html</code> on your webserver with the contents</p>
  
  <pre><code>&lt;script&gt;
      var xhr = new XMLHttpRequest;
      xhr.open('GET', 'test.html');
      xhr.setRequestHeader('Cache-Control', 'no-cache');
      xhr.send();
  &lt;/script&gt;
  </code></pre>
  
  <p>In the chrome debugger on the network tab I see the test.html AJAX call. Status code 200. Now press F5 to reload the page. There is the max-age: 0, and status code 304 Not Modified. </p>
  
  <p>Firefox shows a similar behavior. Intead of just overwriting the request header it modifies it to Cache-Control: no-cache, max-age=0 on F5.</p>
  
  <p>Can I suppress this?</p>