This section provides two different views of DOM API: Flattened View - Everything is a node, and Inheritance View - A hierarchy of inherited interfaces.
The DOM API provides two different approaches to represent an XML/HTML document:
1."Objected Oriented" Approach - A document is represented by a collection of linked objects
that have different interfaces with a hierarchy of inheritance. In other words,
the entire DOM API can be viewed as a hierarchy of inherited interfaces.
This is also called the "Inheritance View of DOM".
In this "Inheritance View of DOM", you need to lean a family of related interfaces:
2. "Everything Is a Node" Approach - A document is represented by a tree of objects
that have a single interface called "Node". In other words,
the entire DOM API can be viewed as an single interface - the Node interface.
This is also called the "Flattened View of DOM".
In this "Flattened View of DOM", you just need to learn one interface, "Node":