title: Removing _dc parameter in Ext
body: <p>Using <a href="http://en.wikipedia.org/wiki/Ext_%28JavaScript_library%29" rel="noreferrer">Ext</a>, default <a href="http://docs.sencha.com/ext-js/4-0/#!/api/Ext.Ajax" rel="noreferrer">Ext.Ajax</a> add to GET-request <code>_dc</code> parameter. For example</p>
  
  <pre><code>GET /ConnViewProcessing/?_dc=1263286227619
  </code></pre>
  
  <p>How to remove this parameter?</p>
  
  <p>PS: it's necessary to manually cache response to <code>ETag</code> and <code>If-None-Match</code>.</p>