code: function (elem)
      {
          // delete unneeded handlers
          if (this._sasl_success_handler) {
              this.deleteHandler(this._sasl_success_handler);
              this._sasl_success_handler = null;
          }
          if (this._sasl_challenge_handler) {
              this.deleteHandler(this._sasl_challenge_handler);
              this._sasl_challenge_handler = null;
          }
  
          if(this._sasl_mechanism)
            this._sasl_mechanism.onFailure();
          this._changeConnectStatus(Strophe.Status.AUTHFAIL, null);
          return false;
      }
docs: PrivateFunction: _sasl_failure_cb
  _Private_ handler for SASL authentication failure.
  
  Parameters:
  (XMLElement) elem - The matching stanza.
  
  Returns:
  false to remove the handler.
   /* jshint unused:false