Each Document has a doctype attribute whose value is either null or a DocumentType object. The DocumentType interface in the DOM Core provides an interface to the list of entities that are defined for the document, and little else because the effect of namespaces and the various XML schema efforts on DTD representation are not clearly understood as of this writing.

The DOM Level 2 doesn't support editing DocumentType nodes.

A NamedNodeMap containing the general entities, both external and internal, declared in the DTD. Parameter entities are not contained. Duplicates are discarded. For example in:

the interface provides access to foo and the first declaration of bar but not the second declaration of bar or baz. Every node in this map also implements the Entity interface.

The DOM Level 2 does not support editing entities, therefore entities cannot be altered in any way.

The internal subset as a string.

The name of DTD; i.e., the name immediately following the DOCTYPE keyword.

A NamedNodeMap containing the notations declared in the DTD. Duplicates are discarded. Every node in this map also implements the Notation interface.

The DOM Level 2 does not support editing notations, therefore notations cannot be altered in any way.

The public identifier of the external subset.

The system identifier of the external subset.