code: function XdrStreamingTransport(transUrl) {
    if (!XDRObject.enabled) {
      throw new Error('Transport created when disabled');
    }
    AjaxBasedTransport.call(this, transUrl, '/xhr_streaming', XhrReceiver, XDRObject);
  }
docs: According to: http://stackoverflow.com/questions/1641507/detect-browser-support-for-cross-domain-xmlhttprequests http://hacks.mozilla.org/2009/07/cross-site-xmlhttprequest-with-cors/