Definition of a layout in the view box.
The type of layout. The layout can be "static", in which case HTML will be injected into the view box, of "template" (the default), in which case the contents of the view box will be derived from the passed in template.
If the type is "static", then the HTML to use in the view box. HTML can be a string, or a function that will return an HTML string.
If the type if "template", then the template to use to generate the HTML for the view box. See.
The HTML to draw.