code: function () {
          var self = this;
  
          self.classes.add('iframe');
          self.canFocus = false;
  
          /*eslint no-script-url:0 */
          return (
            '<iframe id="' + self._id + '" class="' + self.classes + '" tabindex="-1" src="' +
            (self.settings.url || "javascript:''") + '" frameborder="0"></iframe>'
          );
        }
docs: Renders the control as a HTML string.
  
  @method renderHtml
  @return {String} HTML representing the control.