The Document interface is defined in the W3C Document Object Model (DOM) Level 2 Core Specification. (Refer to http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113.)

The Document interface represents the entire HTML or XML document. Conceptually, it is the root of the document tree, and provides the primary access to the document's data.

Since elements, text nodes, comments, processing instructions, etc. cannot exist outside the context of a Document, the Document interface also contains the factory methods needed to create these objects. The Node objects created have a ownerDocument attribute which associates them with the Document within whose context they were created.