The DOMImplementation interface provides a number of methods for performing operations that are independent of any particular instance of the document object model.

See also the Document Object Model (DOM) Level 3 Core Specification.

Creates a DOM Document object of the specified type with its document element.
Note that based on the DocumentType given to create the document, the implementation may instantiate specialized Document objects that support additional features than the "Core", such as "HTML" [DOM Level 2 HTML] . On the other hand, setting the DocumentType after the document was created makes this very unlikely to happen. Alternatively, specialized Document creation methods, such as createHTMLDocument [DOM Level 2 HTML] , can be used to obtain specific types of Document objects.
Parameters
namespaceURIThe namespace URI of the document element to create or null.
qualifiedNameThe qualified name of the document element to be created or null.
doctypeThe type of document to be created or null. When doctype is not null, its Node.ownerDocument attribute is set to the document being created.
Return
A new Document object with its document element. If the NamespaceURI, qualifiedName, and doctype are null, the returned Document is empty with no document element.
Throws
DOMException INVALID_CHARACTER_ERR: Raised if the specified qualified name is not an XML name according to [XML 1.0].
NAMESPACE_ERR: Raised if the qualifiedName is malformed, if the qualifiedName has a prefix and the namespaceURI is null, or if the qualifiedName is null and the namespaceURI is different from null, or if the qualifiedName has a prefix that is "xml" and the namespaceURI is different from " http://www.w3.org/XML/1998/namespace" [XML Namespaces] , or if the DOM implementation does not support the "XML" feature but a non-null namespace URI was provided, since namespaces were defined by XML.
WRONG_DOCUMENT_ERR: Raised if doctype has already been used with a different document or was created from a different implementation.
NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).
@since
DOM Level 2
Creates an empty DocumentType node. Entity declarations and notations are not made available. Entity reference expansions and default attribute additions do not occur..
Parameters
qualifiedNameThe qualified name of the document type to be created.
publicIdThe external subset public identifier.
systemIdThe external subset system identifier.
Return
A new DocumentType node with Node.ownerDocument set to null.
Throws
DOMException INVALID_CHARACTER_ERR: Raised if the specified qualified name is not an XML name according to [XML 1.0].
NAMESPACE_ERR: Raised if the qualifiedName is malformed.
NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).
@since
DOM Level 2
This method returns a specialized object which implements the specialized APIs of the specified feature and version, as specified in . The specialized object may also be obtained by using binding-specific casting methods but is not necessarily expected to, as discussed in . This method also allow the implementation to provide specialized objects which do not support the DOMImplementation interface.
Parameters
featureThe name of the feature requested. Note that any plus sign "+" prepended to the name of the feature will be ignored since it is not significant in the context of this method.
versionThis is the version number of the feature to test.
Return
Returns an object which implements the specialized APIs of the specified feature and version, if any, or null if there is no object which implements interfaces associated with that feature. If the DOMObject returned by this method implements the DOMImplementation interface, it must delegate to the primary core DOMImplementation and not return results inconsistent with the primary core DOMImplementation such as hasFeature, getFeature, etc.
@since
DOM Level 3
Test if the DOM implementation implements a specific feature and version, as specified in .
Parameters
featureThe name of the feature to test.
versionThis is the version number of the feature to test.
Return
true if the feature is implemented in the specified version, false otherwise.