After the name comes a rule that describes what the element can contain. Through this description, the element take on hierarchal relationships with each other. Although the basic bits of the rules are simple, they can be grouped and combined to create quite complex definitions. This table summarizes the element rule definitions. Contents Elements can contain text, other elements, a combination of text and other elements, or they may be empty.
Elements can contain textual data.
Elements can contain only other specified elements and no text. The contained element are called children of the containing element. The containing element is the parent of the child elements. Element can contain a mix of textual data and other specific elements. Empty elements get their value from their attributes.