Throughout the pages for each element, there is a section detailing the
Parent/Content model relationship between a given element and all the
rest of the HTML element. To list ALL applicable elements in each
relationship on every page would be a big waste of space, especially
since there are many categories of behavior that elements can commonly
be grouped in to when identifying these Parent/Content relationships.
These categories are based on those used in the HTML
DTDs to define behavior for the language.