XML in a Nutshell, 3rd Edition

Structure of the DOM Core

The DOM Core interfaces provide generic access to all supported document content types. The DOM also defines a set of HTML-specific interfaces that expose specific document structures, such as tables, paragraphs, and img elements, directly. Besides using these specialized interfaces, you can access the same information using the generic interfaces defined in the core.

Since XML is designed as a venue for creating new, unique, structured markup languages, standards bodies cannot define application-specific interfaces in advance. Instead, the DOM Core interfaces are provided to manipulate document elements in a completely application-independent manner.

The DOM Core is further segregated into the Fundamental and Extended Interfaces. The Fundamental Interfaces are relevant to both XML and HTML documents, whereas the Extended Interfaces deal with XML-only document structures, such as entity declarations and processing instructions. All DOM Core interfaces are derived from the Node interface, which provides a generic set of methods for accessing a document or document fragment’s tree structure and content.