The main HTML element of the widget.
The widget's content will be rendered into it.
You may also leave this unspecified. In this case the main element will be
created detached from the DOM by the widget object itself. You may use the
value the render() function returns to get the element.
The main HTML element of the widget. The widget's content will be rendered into it. You may also leave this unspecified. In this case the main element will be created detached from the DOM by the widget object itself. You may use the value the render() function returns to get the element.