Informal parameters allow exact control over the HTML generated by a component. They may be provided in the page or component specification, or in the HTML template itself.
Components either render a body or remove it. If a component renders its body, the body (the HTML elements and components its HTML tag wraps around) will be rendered, along with any HTML generated by the component itself. If a component removes its body, then the HTML it wraps around will be ignored (and an error is generated if the component wraps around another component).
Most components remove their body; placing HTML within the component's tags is a convienience for WYSIWYG editting of the HTML template.