title: extjs 4.1 download xml file using ajax
body: <p>i want to download a file using extjs 4.1.</p>
  
  <p>The file name is "wsnDataModel.xml".</p>
  
  <p>I've tryed with all things suggested in other posts:</p>
  
  <pre><code>//function invoked clicking a button
  DwDataModel : function(th, h, items) {
      //direct method that build in file in the location calculated below with "certurl" (I've verified)
      Utility.GetDataModel(function(e, z, x) {
          if (z.message) {
              //the server method should give an error message
              Ext.create('AM.view.notification.toast', {
                          title : 'Error',
                          html : z.message,
                          isError : true
                      }).show();
          } else {
              // navigate to get data
              var certurl = 'http://' + window.location.host
                      + '/AdminConsole3/' + e;
              Ext.Ajax.request({
                          method : 'GET',
                          url : 'http://' + window.location.host
                                  + '/AdminConsole3/' + e,
                          success : function(response, opts) {
  //the following navigate and openthe file in the current browser page.
  //I don't want to change the current browser page                               
                         //window.location.href = certurl;
  //the same behaviour with
                         //document.location = certurl;
  
  
                         //and this don't work at all 
                          window.open(certurl,'download');
                          },
                          failure : function(response, opts) {
                              console
                                      .log('server-side failure with status code '
                                              + response.status);
                              console.log('tried to fetch ' + url);
                          }
                      }, this, [certurl]);
          }
      }, th);
  }
  </code></pre>
  
  <p>the "navigation" redirect the application (i don't want to redirect the application) like this:<img src="https://i.stack.imgur.com/1dE9q.png" alt="redirect"></p>
  
  <p>and I'would like to download the file like this image:
  <img src="https://i.stack.imgur.com/pKfNO.png" alt="download"></p>
  
  <p>I think it's very simple. How to do that?</p>
  
  <p>thank you</p>