title: XMLHttpRequest response has no headers in Internet Explorer
body: <p>I'm making an XMLHttpRequest using ExtJS to a service that returns no responseText, just a 204 and the response header <em>TotalNearby</em>. The call works perfectly using Firefox, but with Internet Explorer 8, both alert boxes are empty. What am I doing wrong?</p>
  
  <pre><code>Ext.Ajax.request({
      url: 'services/getNearby',
      method: 'GET',
      params: {
          'lat': 34,
          'lon': -90
      },
      headers: {
          'Authorization': AUTH_TOKEN
      },
      success: function(response) {
          if (response.status == 204) {
              alert(response.getAllResponseHeaders());
              alert(response.getResponseHeader('Total-Nearby'));
          }
      },
      failure: function(response) {
          alert('Server status ' + response.status);
      }
  });
  </code></pre>