title: Assigning a default function to an Ext.Ajax.request failure
body: <p>I make a ton of ajax requests in my application using <code>Ext.Ajax.request</code>.  A lot of times I don't want or have the time to put in any fancy error handling if the request fails, so I end up doing something like this:</p>
  
  <pre><code>    Ext.Ajax.request({
          url: 'requesturl',
          success: function (response) {
              //request successful. do stuff with response
          },
          failure: function () {
              Ext.Msg.alert('Unknown Error', 'Please alert an administrator.');
          }
  </code></pre>
  
  <p>I'm wondering if there's a way I can define a default Ajax request failure function so I don't have to include the failure parameter on every Ajax request I write.</p>