FOM Reference > DOM Support > DOM > Document interface
  
Document interface
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.
doctype attribute
The Document Type Declaration (see DocumentType) associated with this document. For HTML documents as well as XML documents without a document type declaration this returns null. The DOM Level 2 does not support editing the Document Type Declaration. docType cannot be altered in any way, including through the use of methods inherited from the Node interface, such as insertNode or removeNode.
doctype
Access
read-only
Returns
DocumentType
documentElement attribute
This is a convenience attribute that allows direct access to the child node that is the root element of the document. For HTML documents, this is the element with the tagName "HTML".
documentElement
Access
read-only
Returns
Element
implementation attribute
The DOMImplementation object that handles this document. A DOM application may use objects from multiple implementations.
implementation
Access
read-only
Returns
DOMImplementation
createAttribute method
Creates an Attr of the given name. Note that the Attr instance can then be set on an Element using the setAttributeNode method.
To create an attribute with a qualified name and namespace URI, use the createAttributeNS method.
createAttributename
Parameters
Stringname
The name of the attribute.
Returns
Attr. A new Attr object with the nodeName attribute set to name, and localName, prefix, and namespaceURI set to null. The value of the attribute is the empty string.
Throws
DOMException
INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character.
createAttributeNS method
Creates an attribute of the given qualified name and namespace URI. HTML-only DOM implementations do not need to implement this method.
createAttributeNSnamespaceURIqualifiedName
Parameters
StringnamespaceURI
The namespace URI of the attribute to create.
StringqualifiedName
The qualified name of the attribute to instantiate.
Returns
Attr. A new Attr object with the following attributes:
Node.nodeName
qualifiedName
Node.namespaceURI
namespaceURI
Node.prefix
prefix, extracted from qualifiedName, or null if there is no prefix
Node.localName
local name, extracted from qualifiedName
Attr.name
qualifiedName
Node.nodeValue
the empty string
Throws
DOMException
INVALID_CHARACTER_ERR: Raised if the specified qualified name contains an illegal character.
NAMESPACE_ERR: Raised if the qualifiedName is malformed, if the qualifiedName has a prefix and the namespaceURI is null, if the qualifiedName has a prefix that is "xml" and the namespaceURI is different from the xml namespace, or if the qualifiedName is "xmlns" and the namespaceURI is different from the xml namespace.
createCDATASection method
Creates a CDATASection node whose value is the specified string.
createCDATASectiondata
Parameters
Stringdata
The data for the CDATASection contents.
Returns
CDATASection. The new CDATASection object.
Throws
DOMException
NOT_SUPPORTED_ERR: Raised if this document is an HTML document.
createComment method
Creates a Comment node given the specified string.
createCommentdata
Parameters
Stringdata
The data for the node.
Returns
Comment. The new Comment object.
createDocumentFragment method
Creates an empty DocumentFragment object.
createDocumentFragment
Parameters
None
Returns
DocumentFragment. A new DocumentFragment.
createElement method
Creates an element of the type specified. Note that the instance returned implements the Element interface, so attributes can be specified directly on the returned object.
In addition, if there are known attributes with default values, Attr nodes representing them are automatically created and attached to the element.
To create an element with a qualified name and namespace URI, use the createElementNS method.
createElementtagName
Parameters
StringtagName
The name of the element type to instantiate. For XML, this is case-sensitive. For HTML, the tagName parameter may be provided in any case, but it must be mapped to the canonical uppercase form by the DOM implementation.
Returns
Element. A new Element object with the nodeName attribute set to tagName, and localName, prefix, and namespaceURI set to null.
Throws
DOMException
INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character.
createElementNS method
Creates an element of the given qualified name and namespace URI. HTML-only DOM implementations do not need to implement this method.
createElementNSnamespaceURIqualifiedName
Parameters
StringnamespaceURI
The namespace URI of the element to create.
StringqualifiedName
The qualified name of the element type to instantiate.
Returns
Element. A new Element object with the following attributes:
Node.nodeName
qualifiedName
Node.namespaceURI
namespaceURI
Node.prefix
prefix, extracted from qualifiedName, or null if there is no prefix
Node.localName
local name, extracted from qualifiedName
Element.tagName
qualifiedName
Throws
DOMException
INVALID_CHARACTER_ERR: Raised if the specified qualified name contains an illegal character.
NAMESPACE_ERR: Raised if the qualifiedName is malformed, if the qualifiedName has a prefix and the namespaceURI is null, or if the qualifiedName has a prefix that is "xml" and the namespaceURI is different from the XML namespace. [XML Namespaces].
createEntityReference method
Creates an EntityReference object. In addition, if the referenced entity is known, the child list of the EntityReference node is made the same as that of the corresponding Entity node.
* 
If any descendant of the Entity node has an unbound namespace prefix, the corresponding descendant of the created EntityReference node is also unbound; (its namespaceURI is null). The DOM Level 2 does not support any mechanism to resolve namespace prefixes.
createEntityReferencename
Parameters
Stringname
The name of the entity to reference.
Returns
EntityReference. The new EntityReference object.
Throws
DOMException
INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character.
NOT_SUPPORTED_ERR: Raised if this document is an HTML document.
createProcessingInstruction method
Creates a ProcessingInstruction node given the specified name and data strings.
createProcessingInstructiontargetdata
Parameters
Stringtarget
The target part of the processing instruction.
Stringdata
The data for the node.
Returns
ProcessingInstruction. The new ProcessingInstruction object.
Throws
DOMException
INVALID_CHARACTER_ERR: Raised if the specified target contains an illegal character.
NOT_SUPPORTED_ERR: Raised if this document is an HTML document.
createTextNode method
Creates a Text node given the specified string.
createTextNodedata
Parameters
Stringdata
The data for the node.
Returns
Text. The new Text object.
getElementById method
Returns the Element whose ID is given by elementId. If no such element exists, returns null. Behavior is not defined if more than one element has this ID.
* 
The DOM implementation must have information that says which attributes are of type ID. Attributes with the name "ID" are not of type ID unless so defined. Implementations that do not know whether attributes are of type ID or not are expected to return null.
getElementByIdelementId
Parameters
StringelementId
The unique id value for an element.
Returns
Element. The matching element.
getElementsByTagName method
Returns a NodeList of all the Elements with a given tag name in the order in which they are encountered in a preorder traversal of the Document tree.
getElementsByTagNametagName
Parameters
StringtagName
The name of the tag to match on. The special value "*" matches all tags.
Returns
NodeList. A new NodeList object containing all the matched Elements.
getElementsByTagNameNS method
Returns a NodeList of all the Elements with a given local name and namespace URI in the order in which they are encountered in a preorder traversal of the Document tree.
getElementsByTagNameNSnamespaceURIlocalName
Parameters
StringnamespaceURI
The namespace URI of the elements to match on. The special value "*" matches all namespaces.
StringlocalName
The local name of the elements to match on. The special value "*" matches all local names.
Returns
NodeList. A new NodeList object containing all the matched Elements.
importNode method
Imports a node from another document to this document. The returned node has no parent; ( parentNode is null). The source node is not altered or removed from the original document; this method creates a new copy of the source node.
For all nodes, importing a node creates a node object owned by the importing document, with attribute values identical to the source node's nodeName and nodeType , plus the attributes related to namespaces (prefix, localName, and namespaceURI). As in the cloneNode operation on a Node, the source node is not altered.
Additional information is copied as appropriate to the nodeType, attempting to mirror the behavior expected if a fragment of XML or HTML source was copied from one document to another, recognizing that the two documents may have different DTDs in the XML case. The following list describes the specifics for each type of node.
ATTRIBUTE_NODE
The ownerElement attribute is set to null and the specified flag is set to true on the generated Attr. The descendants of the source Attr are recursively imported and the resulting nodes reassembled to form the corresponding subtree.
Note that the deep parameter has no effect on Attr nodes; they always carry their children with them when imported.
DOCUMENT_FRAGMENT_NODE
If the deep option was set to true, the descendants of the source element are recursively imported and the resulting nodes reassembled to form the corresponding subtree. Otherwise, this simply generates an empty DocumentFragment.
DOCUMENT_NODE
Document nodes cannot be imported.
DOCUMENT_TYPE_NODE
DocumentType nodes cannot be imported.
ELEMENT_NODE
Specified attribute nodes of the source element are imported, and the generated Attr nodes are attached to the generated Element. Default attributes are not copied, though if the document being imported into defines default attributes for this element name, those are assigned. If the importNodedeep parameter was set to true, the descendants of the source element are recursively imported and the resulting nodes reassembled to form the corresponding subtree.
ENTITY_NODE
Entity nodes can be imported, however in the current release of the DOM the DocumentType is readonly. Ability to add these imported nodes to a DocumentType will be considered for addition to a future release of the DOM.
On import, the publicId, systemId, and notationName attributes are copied. If a deep import is requested, the descendants of the the source Entity are recursively imported and the resulting nodes reassembled to form the corresponding subtree.
ENTITY_REFERENCE_NODE
Only the EntityReference itself is copied, even if a deep import is requested, since the source and destination documents might have defined the entity differently. If the document being imported into provides a definition for this entity name, its value is assigned.
NOTATION_NODE
Notation nodes can be imported, however in the current release of the DOM the DocumentType is readonly. Ability to add these imported nodes to a DocumentType will be considered for addition to a future release of the DOM.
On import, the publicId and systemId attributes are copied.
Note that the deep parameter has no effect on Notation nodes since they never have any children.
PROCESSING_INSTRUCTION_NODE
The imported node copies its target and data values from those of the source node.
TEXT_NODE, CDATA_SECTION_NODE, COMMENT_NODE
These three types of nodes inheriting from CharacterData copy their data and length attributes from those of the source node.
importNodeimportedNodedeep
Parameters
NodeimportedNode
The node to import.
booleandeep
If true, recursively import the subtree under the specified node; if false, import only the node itself, as explained above. This has no effect on Attr, EntityReference, and Notation nodes.
Returns
Node. The imported node that belongs to this Document.
Throws
DOMException
NOT_SUPPORTED_ERR: Raised if the type of node being imported is not supported.