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WD-DOM-Level-2-19990923

1. Document Object Model Core

Editors
Arnaud Le Hors, W3C
Mike Champion, ArborText (for DOM Level 1 from November 20, 1997)
Steve Byrne, JavaSoft (for DOM Level 1 until November 19, 1997)
Gavin Nicol, Inso EPS (for DOM Level 1)
Lauren Wood, SoftQuad, Inc. (for DOM Level 1)

Table of contents

1.1. Overview of the DOM Core Interfaces

This section defines a minimal set of objects and interfaces for accessing and manipulating document objects. The functionality specified in this section (the Core functionality) is sufficient to allow software developers and web script authors to access and manipulate parsed HTML and XML content inside conforming products. The DOM Core API also allows creation and population of a Document object using only DOM API calls; loading a Document and saving it persistently is left to the product that implements the DOM API.

1.1.1. The DOM Structure Model

The DOM presents documents as a hierarchy of Node objects that also implement other, more specialized interfaces. Some types of nodes may have child nodes of various types, and others are leaf nodes that cannot have anything below them in the document structure. The node types, and which node types they may have as children, are as follows:

The DOM also specifies a NodeList interface to handle ordered lists of Nodes, such as the children of a Node, or the elements returned by the getElementsByTagName method of the Element interface, and also a NamedNodeMap interface to handle unordered sets of nodes referenced by their name attribute, such as the attributes of an Element. NodeList and NamedNodeMap objects in the DOM are "live", that is, changes to the underlying document structure are reflected in all relevant NodeList and NamedNodeMap objects. For example, if a DOM user gets a NodeList object containing the children of an Element, then subsequently adds more children to that element (or removes children, or modifies them), those changes are automatically reflected in the NodeList, without further action on the user's part. Likewise, changes to a Node in the tree are reflected in all references to that Node in NodeList and NamedNodeMap objects.

Finally, the interfaces Text, Comment, and CDATASection all inherit from the CharacterData interface.

1.1.2. Memory Management

Most of the APIs defined by this specification are interfaces rather than classes. That means that an actual implementation need only expose methods with the defined names and specified operation, not actually implement classes that correspond directly to the interfaces. This allows the DOM APIs to be implemented as a thin veneer on top of legacy applications with their own data structures, or on top of newer applications with different class hierarchies. This also means that ordinary constructors (in the Java or C++ sense) cannot be used to create DOM objects, since the underlying objects to be constructed may have little relationship to the DOM interfaces. The conventional solution to this in object-oriented design is to define factory methods that create instances of objects that implement the various interfaces. Objects implementing some interface "X" are created by a "createX()" method on the Document interface; this is because all DOM objects live in the context of a specific Document.

The DOM Level 2 API does not define a standard way to create DOMImplementation objects; actual DOM implementations must provide some proprietary way of bootstrapping these DOM interfaces, and then all other objects can be built from there.

The Core DOM APIs are designed to be compatible with a wide range of languages, including both general-user scripting languages and the more challenging languages used mostly by professional programmers. Thus, the DOM APIs need to operate across a variety of memory management philosophies, from language platforms that do not expose memory management to the user at all, through those (notably Java) that provide explicit constructors but provide an automatic garbage collection mechanism to automatically reclaim unused memory, to those (especially C/C++) that generally require the programmer to explicitly allocate object memory, track where it is used, and explicitly free it for re-use. To ensure a consistent API across these platforms, the DOM does not address memory management issues at all, but instead leaves these for the implementation. Neither of the explicit language bindings devised by the DOM Working Group (for ECMAScript and Java) require any memory management methods, but DOM bindings for other languages (especially C or C++) may require such support. These extensions will be the responsibility of those adapting the DOM API to a specific language, not the DOM WG.

1.1.3. Naming Conventions

While it would be nice to have attribute and method names that are short, informative, internally consistent, and familiar to users of similar APIs, the names also should not clash with the names in legacy APIs supported by DOM implementations. Furthermore, both OMG IDL and ECMAScript have significant limitations in their ability to disambiguate names from different namespaces that makes it difficult to avoid naming conflicts with short, familiar names. So, DOM names tend to be long and quite descriptive in order to be unique across all environments.

The Working Group has also attempted to be internally consistent in its use of various terms, even though these may not be common distinctions in other APIs. For example, we use the method name "remove" when the method changes the structural model, and the method name "delete" when the method gets rid of something inside the structure model. The thing that is deleted is not returned. The thing that is removed may be returned, when it makes sense to return it.

1.1.4. Inheritance vs Flattened Views of the API

The DOM Core APIs present two somewhat different sets of interfaces to an XML/HTML document; one presenting an "object oriented" approach with a hierarchy of inheritance, and a "simplified" view that allows all manipulation to be done via the Node interface without requiring casts (in Java and other C-like languages) or query interface calls in COM environments. These operations are fairly expensive in Java and COM, and the DOM may be used in performance-critical environments, so we allow significant functionality using just the Node interface. Because many other users will find the inheritance hierarchy easier to understand than the "everything is a Node" approach to the DOM, we also support the full higher-level interfaces for those who prefer a more object-oriented API.

In practice, this means that there is a certain amount of redundancy in the API. The Working Group considers the "inheritance" approach the primary view of the API, and the full set of functionality on Node to be "extra" functionality that users may employ, but that does not eliminate the need for methods on other interfaces that an object-oriented analysis would dictate. (Of course, when the O-O analysis yields an attribute or method that is identical to one on the Node interface, we don't specify a completely redundant one). Thus, even though there is a generic nodeName attribute on the Node interface, there is still a tagName attribute on the Element interface; these two attributes must contain the same value, but the Working Group considers it worthwhile to support both, given the different constituencies the DOM API must satisfy.

1.1.5. The DOMString type

To ensure interoperability, the DOM specifies the following:

  • Type Definition DOMString

    A DOMString is a sequence of 16-bit units.


    IDL Definition
    typedef sequence<unsigned short> DOMString;
    

  • Applications must encode DOMString using UTF-16 (defined in Appendix C.3 of [UNICODE] and Amendment 1 of [ISO-10646]).
    The UTF-16 encoding was chosen because of its widespread industry practice. Please note that for both HTML and XML, the document character set (and therefore the notation of numeric character references) is based on UCS [ISO-10646]. A single numeric character reference in a source document may therefore in some cases correspond to two 16-bit units in a DOMString (a high surrogate and a low surrogate). Note: Even though the DOM defines the name of the string type to be DOMString, bindings may use different names. For, example for Java, DOMString is bound to the String type because it also uses UTF-16 as its encoding.
Note: As of August 1998, the OMG IDL specification included a wstring type. However, that definition did not meet the interoperability criteria of the DOM API since it relied on encoding negotiation to decide the width of a character.

1.1.6. Case sensitivity in the DOM

The DOM has many interfaces that imply string matching. HTML processors generally assume an uppercase (less often, lowercase) normalization of names for such things as elements, while XML is explicitly case sensitive. For the purposes of the DOM, string matching is performed purely by binary comparison of the 16-bit units of the DOMString. As such, the DOM assumes that any normalizations take place in the processor, before the DOM structures are built.

This then raises the issue of exactly what normalizations occur. The W3C I18N working group is in the process of defining exactly which normalizations are necessary for applications implementing the DOM.

1.1.7. XML Namespaces

The DOM Level 2 supports XML namespaces [Namespaces] by augmenting several interfaces of the DOM Level 1 Core to allow creating and manipulating elements and attributes associated to a namespace.

As far as the DOM is concerned, special attributes used for declaring XML namespaces are still exposed and can be manipulated just like any other attribute. Moving a node within a document, using the DOM, in no case results in a change of its namespace prefix or namespace URI. Similarly, creating a node with a namespace prefix and namespace URI, or changing the namespace prefix of a node, does not result in any addition, removal, or modification of any special attributes for declaring the appropriate XML namespaces. Applications are therefore responsible for declaring every namespace in use when saving a document into XML.

The new methods, such as createElementNS and createAttributeNS of the Document interface, are meant to be used by namespace aware applications. Simple applications that do not use namespaces can use the DOM Level 1 methods, such as createElement and createAttribute. Elements and attributes created in this way do not have any namespace prefix or namespace URI.

1.2. Fundamental Interfaces

The interfaces within this section are considered fundamental, and must be fully implemented by all conforming implementations of the DOM, including all HTML DOM implementations, unless otherwise specified.

Exception DOMException

DOM operations only raise exceptions in "exceptional" circumstances, i.e., when an operation is impossible to perform (either for logical reasons, because data is lost, or because the implementation has become unstable). In general, DOM methods return specific error values in ordinary processing situation, such as out-of-bound errors when using NodeList.

Implementations may raise other exceptions under other circumstances. For example, implementations may raise an implementation-dependent exception if a null argument is passed.

Some languages and object systems do not support the concept of exceptions. For such systems, error conditions may be indicated using native error reporting mechanisms. For some bindings, for example, methods may return error codes similar to those listed in the corresponding method descriptions.


IDL Definition
exception DOMException {
  unsigned short   code;
};

// ExceptionCode
const unsigned short      INDEX_SIZE_ERR                 = 1;
const unsigned short      DOMSTRING_SIZE_ERR             = 2;
const unsigned short      HIERARCHY_REQUEST_ERR          = 3;
const unsigned short      WRONG_DOCUMENT_ERR             = 4;
const unsigned short      INVALID_CHARACTER_ERR          = 5;
const unsigned short      NO_DATA_ALLOWED_ERR            = 6;
const unsigned short      NO_MODIFICATION_ALLOWED_ERR    = 7;
const unsigned short      NOT_FOUND_ERR                  = 8;
const unsigned short      NOT_SUPPORTED_ERR              = 9;
const unsigned short      INUSE_ATTRIBUTE_ERR            = 10;

Definition group ExceptionCode

An integer indicating the type of error generated.

Defined Constants
INDEX_SIZE_ERR If index or size is negative, or greater than the allowed value
DOMSTRING_SIZE_ERR If the specified range of text does not fit into a DOMString
HIERARCHY_REQUEST_ERR If any node is inserted somewhere it doesn't belong
WRONG_DOCUMENT_ERR If a node is used in a different document than the one that created it (that doesn't support it)
INVALID_CHARACTER_ERR If an invalid character is specified, such as in a name.
NO_DATA_ALLOWED_ERR If data is specified for a node which does not support data
NO_MODIFICATION_ALLOWED_ERR If an attempt is made to modify an object where modifications are not allowed
NOT_FOUND_ERR If an attempt was made to reference a node in a context where it does not exist
NOT_SUPPORTED_ERR If the implementation does not support the type of object requested
INUSE_ATTRIBUTE_ERR If an attempt is made to add an attribute that is already inuse elsewhere
Interface DOMImplementation

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


IDL Definition
interface DOMImplementation {
  boolean            hasFeature(in DOMString feature, 
                                in DOMString version);
  // Introduced in DOM Level 2:
  DocumentType       createDocumentType(in DOMString qualifiedName, 
                                        in DOMString publicID, 
                                        in DOMString systemID);
  // Introduced in DOM Level 2:
  Document           createDocument(in DOMString namespaceURI, 
                                    in DOMString qualifiedName, 
                                    in DocumentType doctype)
                                        raises(DOMException);
};

Methods
hasFeature
Test if the DOM implementation implements a specific feature.
Parameters

DOMString

feature

The package name of the feature to test (case-insensitive). The legal values are defined throughout this specification. The DOM Level 2 includes "HTML", "XML", as well as the several others.

DOMString

version

This is the version number of the package name to test. In Level 2, this is the string "2.0". If the version is not specified, supporting any version of the feature will cause the method to return true.

Return Value

boolean

true if the feature is implemented in the specified version, false otherwise.

No Exceptions

createDocumentType introduced in DOM Level 2
Creates an empty DocumentType node. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

qualifiedName

The qualified name of the document type to be created.

DOMString

publicID

The document type public identifier.

DOMString

systemID

The document type system identifier.

Return Value

DocumentType

A new DocumentType node with Node.ownerDocument set to null.

No Exceptions

createDocument introduced in DOM Level 2
Creates an XML Document object of the specified type with its document element. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the document element to create, or null.

DOMString

qualifiedName

The qualified name of the document element to be created.

DocumentType

doctype

The 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 Value

Document

A new Document object.

Exceptions

DOMException

WRONG_DOCUMENT_ERR: Raised if doctype has already been used with a different document.

Interface DocumentFragment

DocumentFragment is a "lightweight" or "minimal" Document object. It is very common to want to be able to extract a portion of a document's tree or to create a new fragment of a document. Imagine implementing a user command like cut or rearranging a document by moving fragments around. It is desirable to have an object which can hold such fragments and it is quite natural to use a Node for this purpose. While it is true that a Document object could fulfill this role, a Document object can potentially be a heavyweight object, depending on the underlying implementation. What is really needed for this is a very lightweight object. DocumentFragment is such an object.

Furthermore, various operations -- such as inserting nodes as children of another Node -- may take DocumentFragment objects as arguments; this results in all the child nodes of the DocumentFragment being moved to the child list of this node.

The children of a DocumentFragment node are zero or more nodes representing the tops of any sub-trees defining the structure of the document. DocumentFragment nodes do not need to be well-formed XML documents (although they do need to follow the rules imposed upon well-formed XML parsed entities, which can have multiple top nodes). For example, a DocumentFragment might have only one child and that child node could be a Text node. Such a structure model represents neither an HTML document nor a well-formed XML document.

When a DocumentFragment is inserted into a Document (or indeed any other Node that may take children) the children of the DocumentFragment and not the DocumentFragment itself are inserted into the Node. This makes the DocumentFragment very useful when the user wishes to create nodes that are siblings; the DocumentFragment acts as the parent of these nodes so that the user can use the standard methods from the Node interface, such as insertBefore and appendChild.


IDL Definition
interface DocumentFragment : Node {
};

Interface Document

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.


IDL Definition
interface Document : Node {
  readonly attribute DocumentType     doctype;
  readonly attribute DOMImplementation  implementation;
  readonly attribute Element          documentElement;
  Element            createElement(in DOMString tagName)
                                        raises(DOMException);
  DocumentFragment   createDocumentFragment();
  Text               createTextNode(in DOMString data);
  Comment            createComment(in DOMString data);
  CDATASection       createCDATASection(in DOMString data)
                                        raises(DOMException);
  ProcessingInstruction createProcessingInstruction(in DOMString target, 
                                                    in DOMString data)
                                        raises(DOMException);
  Attr               createAttribute(in DOMString name)
                                        raises(DOMException);
  EntityReference    createEntityReference(in DOMString name)
                                        raises(DOMException);
  NodeList           getElementsByTagName(in DOMString tagname);
  // Introduced in DOM Level 2:
  Node               importNode(in Node importedNode, 
                                in boolean deep)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  Element            createElementNS(in DOMString namespaceURI, 
                                     in DOMString qualifiedName)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  Attr               createAttributeNS(in DOMString namespaceURI, 
                                       in DOMString qualifiedName)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  NodeList           getElementsByTagNameNS(in DOMString namespaceURI, 
                                            in DOMString localName);
};

Attributes
doctype of type DocumentType, readonly
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, therefore docType cannot be altered in any way, including through the use of methods, such as insertNode or removeNode, inherited from Node.

implementation of type DOMImplementation, readonly
The DOMImplementation object that handles this document. A DOM application may use objects from multiple implementations.

documentElement of type Element, readonly
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".

Methods
createElement
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.
Parameters

DOMString

tagName

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.

Return Value

Element

A new Element object.

Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

createDocumentFragment
Creates an empty DocumentFragment object.
Return Value
No Parameters
No Exceptions

createTextNode
Creates a Text node given the specified string.
Parameters

DOMString

data

The data for the node.

Return Value

Text

The new Text object.

No Exceptions

createComment
Creates a Comment node given the specified string.
Parameters

DOMString

data

The data for the node.

Return Value

Comment

The new Comment object.

No Exceptions

createCDATASection
Creates a CDATASection node whose value is the specified string.
Parameters

DOMString

data

The data for the CDATASection contents.

Return Value

CDATASection

The new CDATASection object.

Exceptions

DOMException

NOT_SUPPORTED_ERR: Raised if this document is an HTML document.

createProcessingInstruction
Creates a ProcessingInstruction node given the specified name and data strings.
Parameters

DOMString

target

The target part of the processing instruction.

DOMString

data

The data for the node.

Return Value
Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if an invalid character is specified.

NOT_SUPPORTED_ERR: Raised if this document is an HTML document.

createAttribute
Creates an Attr of the given name. Note that the Attr instance can then be set on an Element using the setAttribute method.
To create an attribute with a qualified name and namespace URI, use the createAttributeNS method.
Parameters

DOMString

name

The name of the attribute.

Return Value

Attr

A new Attr object.

Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

createEntityReference
Creates an EntityReference object.
Parameters

DOMString

name

The name of the entity to reference.

Return Value
Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

NOT_SUPPORTED_ERR: Raised if this document is an HTML document.

getElementsByTagName
Returns a NodeList of all the Elements with a given tag name in the order in which they would be encountered in a preorder traversal of the Document tree.
Parameters

DOMString

tagname

The name of the tag to match on. The special value "*" matches all tags.

Return Value

NodeList

A new NodeList object containing all the matched Elements.

No Exceptions

importNode introduced in DOM Level 2
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 and namespaces URI). 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 every type of node.
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 importNode deep parameter was set to true, the descendants of the source element will be recursively imported and the resulting nodes reassembled to form the corresponding subtree.
ATTRIBUTE_NODE
The specified flag is set to true on the generated Attr. The descendants of the the source Attr are recursively imported and the resulting nodes reassembled to form the corresponding subtree.
Note that the deep parameter does not apply to Attr nodes; they always carry their children with them when imported.
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.
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.
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 is recursively imported and the resulting nodes reassembled to form the corresponding subtree.
PROCESSING_INSTRUCTION_NODE
The imported node copies its target and data values from those of the source node.
DOCUMENT_NODE
Document nodes cannot be imported.
DOCUMENT_TYPE_NODE
DocumentType nodes cannot be imported.
DOCUMENT_FRAGMENT_NODE
If the deep option was set true, the descendants of the source element will be recursively imported and the resulting nodes reassembled to form the corresponding subtree. Otherwise, this simply generates an empty DocumentFragment.
NOTATION_NODE
Notation nodes 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 does not apply to Notation nodes since they never have any children.
Parameters

Node

importedNode

The node to import.

boolean

deep

If true, recursively import the subtree under the specified node; if false, import only the node itself, as explained above. This does not apply to Attr, EntityReference, and Notation nodes.

Return Value

Node

The imported node that belongs to this Document.

Exceptions

DOMException

NOT_SUPPORTED_ERR: Raised if the type of node being imported is not supported.

createElementNS introduced in DOM Level 2
Creates an element of the given qualified name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the element to create. When it is null or an empty string, this method behaves like createElement.

DOMString

qualifiedName

The qualified name of the element type to instantiate.

Return Value

Element

A new Element object with the following attributes:
AttributeValue
Node.nodeNamequalifiedName
Node.namespaceNamenamespaceURI
Node.prefixprefix, extracted from qualifiedName, or null if there is no prefix
Node.localNamelocal name, extracted from qualifiedName
Element.tagNamequalifiedName

Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

createAttributeNS introduced in DOM Level 2
Creates an attribute of the given qualified name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the attribute to create. When it is null or an empty string, this method behaves like createAttribute.

DOMString

qualifiedName

The qualified name of the attribute to instantiate.

Return Value

Attr

A new Attr object with the following attributes:
AttributeValue
Node.nodeNamequalifiedName
Node.namespaceNamenamespaceURI
Node.prefixprefix, extracted from qualifiedName, or null if there is no prefix
Node.localNamelocal name, extracted from qualifiedName
Attr.namequalifiedName

Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

getElementsByTagNameNS introduced in DOM Level 2
Returns a NodeList of all the Elements with a given local name and namespace URI in the order in which they would be encountered in a preorder traversal of the Document tree.
Parameters

DOMString

namespaceURI

The namespace URI of the elements to match on. The special value "*" matches all namespaces. When it is null or an empty string, this method behaves like getElementsByTagName.

DOMString

localName

The local name of the elements to match on. The special value "*" matches all local names.

Return Value

NodeList

A new NodeList object containing all the matched Elements.

No Exceptions

Interface Node

The Node interface is the primary datatype for the entire Document Object Model. It represents a single node in the document tree. While all objects implementing the Node interface expose methods for dealing with children, not all objects implementing the Node interface may have children. For example, Text nodes may not have children, and adding children to such nodes results in a DOMException being raised.

The attributes nodeName, nodeValue and attributes are included as a mechanism to get at node information without casting down to the specific derived interface. In cases where there is no obvious mapping of these attributes for a specific nodeType (e.g., nodeValue for an Element or attributes for a Comment), this returns null. Note that the specialized interfaces may contain additional and more convenient mechanisms to get and set the relevant information.


IDL Definition
interface Node {
  // NodeType
  const unsigned short      ELEMENT_NODE                   = 1;
  const unsigned short      ATTRIBUTE_NODE                 = 2;
  const unsigned short      TEXT_NODE                      = 3;
  const unsigned short      CDATA_SECTION_NODE             = 4;
  const unsigned short      ENTITY_REFERENCE_NODE          = 5;
  const unsigned short      ENTITY_NODE                    = 6;
  const unsigned short      PROCESSING_INSTRUCTION_NODE    = 7;
  const unsigned short      COMMENT_NODE                   = 8;
  const unsigned short      DOCUMENT_NODE                  = 9;
  const unsigned short      DOCUMENT_TYPE_NODE             = 10;
  const unsigned short      DOCUMENT_FRAGMENT_NODE         = 11;
  const unsigned short      NOTATION_NODE                  = 12;

  readonly attribute DOMString        nodeName;
           attribute DOMString        nodeValue;
                                        // raises(DOMException) on setting
                                        // raises(DOMException) on retrieval

  readonly attribute unsigned short   nodeType;
  readonly attribute Node             parentNode;
  readonly attribute NodeList         childNodes;
  readonly attribute Node             firstChild;
  readonly attribute Node             lastChild;
  readonly attribute Node             previousSibling;
  readonly attribute Node             nextSibling;
  readonly attribute NamedNodeMap     attributes;
  // Modified in DOM Level 2:
  readonly attribute Document         ownerDocument;
  Node               insertBefore(in Node newChild, 
                                  in Node refChild)
                                        raises(DOMException);
  Node               replaceChild(in Node newChild, 
                                  in Node oldChild)
                                        raises(DOMException);
  Node               removeChild(in Node oldChild)
                                        raises(DOMException);
  Node               appendChild(in Node newChild)
                                        raises(DOMException);
  boolean            hasChildNodes();
  Node               cloneNode(in boolean deep);
  // Introduced in DOM Level 2:
  boolean            supports(in DOMString feature, 
                              in DOMString version);
  // Introduced in DOM Level 2:
  readonly attribute DOMString        namespaceURI;
  // Introduced in DOM Level 2:
           attribute DOMString        prefix;
                                        // raises(DOMException) on setting

  // Introduced in DOM Level 2:
  readonly attribute DOMString        localName;
};

Definition group NodeType

An integer indicating which type of node this is.

Defined Constants
ELEMENT_NODE The node is a Element.
ATTRIBUTE_NODE The node is an Attr.
TEXT_NODE The node is a Text node.
CDATA_SECTION_NODE The node is a CDATASection.
ENTITY_REFERENCE_NODE The node is an EntityReference.
ENTITY_NODE The node is an Entity.
PROCESSING_INSTRUCTION_NODE The node is a ProcessingInstruction.
COMMENT_NODE The node is a Comment.
DOCUMENT_NODE The node is a Document.
DOCUMENT_TYPE_NODE The node is a DocumentType.
DOCUMENT_FRAGMENT_NODE The node is a DocumentFragment.
NOTATION_NODE The node is a Notation.

The values of nodeName, nodeValue, and attributes vary according to the node type as follows:
nodeNamenodeValueattributes
ElementtagNamenullNamedNodeMap
Attrname of attributevalue of attributenull
Text#textcontent of the text nodenull
CDATASection#cdata-sectioncontent of the CDATA Sectionnull
EntityReferencename of entity referencednullnull
Entityentity namenullnull
ProcessingInstructiontargetentire content excluding the targetnull
Comment#commentcontent of the commentnull
Document#documentnullnull
DocumentTypedocument type namenullnull
DocumentFragment#document-fragmentnullnull
Notationnotation namenullnull

Attributes
nodeName of type DOMString, readonly
The name of this node, depending on its type; see the table above.

nodeValue of type DOMString
The value of this node, depending on its type; see the table above. When it is defined to be null, setting it has no effect.
Exceptions on setting

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.

Exceptions on retrieval

DOMException

DOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in a DOMString variable on the implementation platform.

nodeType of type unsigned short, readonly
A code representing the type of the underlying object, as defined above.

parentNode of type Node, readonly
The parent of this node. All nodes, except Attr, Document, DocumentFragment, Entity, and Notation may have a parent. However, if a node has just been created and not yet added to the tree, or if it has been removed from the tree, this is null.

childNodes of type NodeList, readonly
A NodeList that contains all children of this node. If there are no children, this is a NodeList containing no nodes. The content of the returned NodeList is "live" in the sense that, for instance, changes to the children of the node object that it was created from are immediately reflected in the nodes returned by the NodeList accessors; it is not a static snapshot of the content of the node. This is true for every NodeList, including the ones returned by the getElementsByTagName method.

firstChild of type Node, readonly
The first child of this node. If there is no such node, this returns null.

lastChild of type Node, readonly
The last child of this node. If there is no such node, this returns null.

previousSibling of type Node, readonly
The node immediately preceding this node. If there is no such node, this returns null.

nextSibling of type Node, readonly
The node immediately following this node. If there is no such node, this returns null.

attributes of type NamedNodeMap, readonly
A NamedNodeMap containing the attributes of this node (if it is an Element) or null otherwise.

ownerDocument of type Document, readonly, modified in DOM Level 2
The Document object associated with this node. This is also the Document object used to create new nodes. When this node is a Document or a DocumentType, which is not used with any Document yet, this is null.

namespaceURI of type DOMString, readonly, introduced in DOM Level 2
The namespace URI of this node, or null if it is unspecified. When this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE, this is always null and setting it has no effect.
This is not a computed value that is the result of a namespace lookup based on an examination of the namespace declarations in scope. It is merely the namespace URI given at creation time.
For nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is null.

prefix of type DOMString, introduced in DOM Level 2
The namespace prefix of this node, or null if it is unspecified. When this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this is always null and setting it has no effect.
For nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is null.
Note that setting this attribute changes the nodeName attribute, which holds the qualified name, as well as the tagName and name attributes of the Element and Attr interfaces, when applicable.
Exceptions on setting

DOMException

INVALID_CHARACTER_ERR: Raised if the specified prefix contains an invalid character.

localName of type DOMString, readonly, introduced in DOM Level 2
Returns the local part of the qualified name of this node.
For nodes created with a DOM Level 1 method, such as createElement from the Document interface, and for nodes of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this is the same as the nodeName attribute.

Methods
insertBefore
Inserts the node newChild before the existing child node refChild. If refChild is null, insert newChild at the end of the list of children.
If newChild is a DocumentFragment object, all of its children are inserted, in the same order, before refChild. If the newChild is already in the tree, it is first removed.
Parameters

Node

newChild

The node to insert.

Node

refChild

The reference node, i.e., the node before which the new node must be inserted.

Return Value

Node

The node being inserted.

Exceptions

DOMException

HIERARCHY_REQUEST_ERR: Raised if this node is of a type that does not allow children of the type of the newChild node, or if the node to insert is one of this node's ancestors.

WRONG_DOCUMENT_ERR: Raised if newChild was created from a different document than the one that created this node.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

NOT_FOUND_ERR: Raised if refChild is not a child of this node.

replaceChild
Replaces the child node oldChild with newChild in the list of children, and returns the oldChild node. If the newChild is already in the tree, it is first removed.
Parameters

Node

newChild

The new node to put in the child list.

Node

oldChild

The node being replaced in the list.

Return Value

Node

The node replaced.

Exceptions

DOMException

HIERARCHY_REQUEST_ERR: Raised if this node is of a type that does not allow children of the type of the newChild node, or it the node to put in is one of this node's ancestors.

WRONG_DOCUMENT_ERR: Raised if newChild was created from a different document than the one that created this node.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

NOT_FOUND_ERR: Raised if oldChild is not a child of this node.

removeChild
Removes the child node indicated by oldChild from the list of children, and returns it.
Parameters

Node

oldChild

The node being removed.

Return Value

Node

The node removed.

Exceptions

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

NOT_FOUND_ERR: Raised if oldChild is not a child of this node.

appendChild
Adds the node newChild to the end of the list of children of this node. If the newChild is already in the tree, it is first removed.
Parameters

Node

newChild

The node to add.

If it is a DocumentFragment object, the entire contents of the document fragment are moved into the child list of this node

Return Value

Node

The node added.

Exceptions

DOMException

HIERARCHY_REQUEST_ERR: Raised if this node is of a type that does not allow children of the type of the newChild node, or if the node to append is one of this node's ancestors.

WRONG_DOCUMENT_ERR: Raised if newChild was created from a different document than the one that created this node.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

hasChildNodes
This is a convenience method to allow easy determination of whether a node has any children.
Return Value

boolean

true if the node has any children, false if the node has no children.

No Parameters
No Exceptions

cloneNode
Returns a duplicate of this node, i.e., serves as a generic copy constructor for nodes. The duplicate node has no parent (parentNode returns null.).
Cloning an Element copies all attributes and their values, including those generated by the XML processor to represent defaulted attributes, but this method does not copy any text it contains unless it is a deep clone, since the text is contained in a child Text node. Cloning any other type of node simply returns a copy of this node.
Parameters

boolean

deep

If true, recursively clone the subtree under the specified node; if false, clone only the node itself (and its attributes, if it is an Element).

Return Value

Node

The duplicate node.

No Exceptions

supports introduced in DOM Level 2
Tests whether the DOM implementation implements a specific feature and that feature is supported by this node.
Parameters

DOMString

feature

The package name of the feature to test. This is the same name as what can be passed to the method hasFeature on DOMImplementation.

DOMString

version

This is the version number of the package name to test. In Level 2, version 1, this is the string "2.0". If the version is not specified, supporting any version of the feature will cause the method to return true.

Return Value

boolean

Returns true if this node defines a subtree within which the specified feature is supported, false otherwise.

No Exceptions

Interface NodeList

The NodeList interface provides the abstraction of an ordered collection of nodes, without defining or constraining how this collection is implemented.

The items in the NodeList are accessible via an integral index, starting from 0.


IDL Definition
interface NodeList {
  Node               item(in unsigned long index);
  readonly attribute unsigned long    length;
};

Attributes
length of type unsigned long, readonly
The number of nodes in the list. The range of valid child node indices is 0 to length-1 inclusive.

Methods
item
Returns the indexth item in the collection. If index is greater than or equal to the number of nodes in the list, this returns null.
Parameters

unsigned long

index

Index into the collection.

Return Value

Node

The node at the indexth position in the NodeList, or null if that is not a valid index.

No Exceptions

Interface NamedNodeMap

Objects implementing the NamedNodeMap interface are used to represent collections of nodes that can be accessed by name. Note that NamedNodeMap does not inherit from NodeList; NamedNodeMaps are not maintained in any particular order. Objects contained in an object implementing NamedNodeMap may also be accessed by an ordinal index, but this is simply to allow convenient enumeration of the contents of a NamedNodeMap, and does not imply that the DOM specifies an order to these Nodes.


IDL Definition
interface NamedNodeMap {
  Node               getNamedItem(in DOMString name);
  Node               setNamedItem(in Node arg)
                                        raises(DOMException);
  Node               removeNamedItem(in DOMString name)
                                        raises(DOMException);
  Node               item(in unsigned long index);
  readonly attribute unsigned long    length;
  // Introduced in DOM Level 2:
  Node               getNamedItemNS(in DOMString namespaceURI, 
                                    in DOMString localName);
  // Introduced in DOM Level 2:
  Node               removeNamedItemNS(in DOMString namespaceURI, 
                                       in DOMString name)
                                        raises(DOMException);
};

Attributes
length of type unsigned long, readonly
The number of nodes in the map. The range of valid child node indices is 0 to length-1 inclusive.

Methods
getNamedItem
Retrieves a node specified by name.
Parameters

DOMString

name

Name of a node to retrieve.

Return Value

Node

A Node (of any type) with the specified name, or null if the specified name did not identify any node in the map.

No Exceptions

setNamedItem
Adds a node using its nodeName attribute, which is the qualified name when applicable.
As the nodeName attribute is used to derive the name which the node must be stored under, multiple nodes of certain types (those that have a "special" string value) cannot be stored as the names would clash. This is seen as preferable to allowing nodes to be aliased.
Parameters

Node

arg

A node to store in a named node map. The node will later be accessible using the value of the nodeName attribute of the node. If a node with that name is already present in the map, it is replaced by the new one.

Return Value

Node

If the new Node replaces an existing node with the same name the previously existing Node is returned, otherwise null is returned.

Exceptions

DOMException

WRONG_DOCUMENT_ERR: Raised if arg was created from a different document than the one that created the NamedNodeMap.

NO_MODIFICATION_ALLOWED_ERR: Raised if this NamedNodeMap is readonly.

INUSE_ATTRIBUTE_ERR: Raised if arg is an Attr that is already an attribute of another Element object. The DOM user must explicitly clone Attr nodes to re-use them in other elements.

removeNamedItem
Removes a node specified by name.
Parameters

DOMString

name

The name of a node to remove. When this NamedNodeMap contains the attributes attached to an element, as returned by the attributes attribute of the Node interface, if the removed attribute is known to have a default value, an attribute immediately appears containing the default value.

Return Value

Node

The node removed from the map if a node with such a name exists.

Exceptions

DOMException

NOT_FOUND_ERR: Raised if there is no node named name in the map.

item
Returns the indexth item in the map. If index is greater than or equal to the number of nodes in the map, this returns null.
Parameters

unsigned long

index

Index into the map.

Return Value

Node

The node at the indexth position in the NamedNodeMap, or null if that is not a valid index.

No Exceptions

getNamedItemNS introduced in DOM Level 2
Retrieves a node specified by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the node to retrieve. When it is null or an empty string, this method behaves like getNamedItem.

DOMString

localName

The local name of the node to retrieve.

Return Value

Node

A Node (of any type) with the specified name, or null if the specified name did not identify any node in the map.

No Exceptions

removeNamedItemNS introduced in DOM Level 2
Removes a node specified by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the node to remove. When it is null or an empty string, this method behaves like removeNamedItem.

DOMString

name

The local name of the node to remove. When this NamedNodeMap contains the attributes attached to an element, as returned by the attributes attribute of the Node interface, if the removed attribute is known to have a default value, an attribute immediately appears containing the default value.

Return Value

Node

The node removed from the map if a node with such a local name and namespace URI exists.

Exceptions

DOMException

NOT_FOUND_ERR: Raised if there is no node named name in the map.

Interface CharacterData

The CharacterData interface extends Node with a set of attributes and methods for accessing character data in the DOM. For clarity this set is defined here rather than on each object that uses these attributes and methods. No DOM objects correspond directly to CharacterData, though Text and others do inherit the interface from it. All offsets in this interface start from 0.


IDL Definition
interface CharacterData : Node {
           attribute DOMString        data;
                                        // raises(DOMException) on setting
                                        // raises(DOMException) on retrieval

  readonly attribute unsigned long    length;
  DOMString          substringData(in unsigned long offset, 
                                   in unsigned long count)
                                        raises(DOMException);
  void               appendData(in DOMString arg)
                                        raises(DOMException);
  void               insertData(in unsigned long offset, 
                                in DOMString arg)
                                        raises(DOMException);
  void               deleteData(in unsigned long offset, 
                                in unsigned long count)
                                        raises(DOMException);
  void               replaceData(in unsigned long offset, 
                                 in unsigned long count, 
                                 in DOMString arg)
                                        raises(DOMException);
};

Attributes
data of type DOMString
The character data of the node that implements this interface. The DOM implementation may not put arbitrary limits on the amount of data that may be stored in a CharacterData node. However, implementation limits may mean that the entirety of a node's data may not fit into a single DOMString. In such cases, the user may call substringData to retrieve the data in appropriately sized pieces.
Exceptions on setting

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.

Exceptions on retrieval

DOMException

DOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in a DOMString variable on the implementation platform.

length of type unsigned long, readonly
The number of 16-bit units that are available through data and the substringData method below. This may have the value zero, i.e., CharacterData nodes may be empty.

Methods
substringData
Extracts a range of data from the node.
Parameters

unsigned long

offset

Start offset of substring to extract.

unsigned long

count

The number of 16-bit units to extract.

Return Value

DOMString

The specified substring. If the sum of offset and count exceeds the length, then all 16-bit units to the end of the data are returned.

Exceptions

DOMException

INDEX_SIZE_ERR: Raised if the specified offset is negative or greater than the number of 16-bit units in data, or if the specified count is negative.

DOMSTRING_SIZE_ERR: Raised if the specified range of text does not fit into a DOMString.

appendData
Append the string to the end of the character data of the node. Upon success, data provides access to the concatenation of data and the DOMString specified.
Parameters

DOMString

arg

The DOMString to append.

Exceptions

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

insertData
Insert a string at the specified character offset.
Parameters

unsigned long

offset

The character offset at which to insert.

DOMString

arg

The DOMString to insert.

Exceptions

DOMException

INDEX_SIZE_ERR: Raised if the specified offset is negative or greater than the number of 16-bit units in data.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

deleteData
Remove a range of 16-bit units from the node. Upon success, data and length reflect the change.
Parameters

unsigned long

offset

The offset from which to start removing.

unsigned long

count

The number of 16-bit units to delete. If the sum of offset and count exceeds length then all 16-bit units from offset to the end of the data are deleted.

Exceptions

DOMException

INDEX_SIZE_ERR: Raised if the specified offset is negative or greater than the number of 16-bit units in data, or if the specified count is negative.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

replaceData
Replace the characters starting at the specified 16-bit unit offset with the specified string.
Parameters

unsigned long

offset

The offset from which to start replacing.

unsigned long

count

The number of 16-bit units to replace. If the sum of offset and count exceeds length, then all 16-bit units to the end of the data are replaced (i.e., the effect is the same as a remove method call with the same range, followed by an append method invocation).

DOMString

arg

The DOMString with which the range must be replaced.

Exceptions

DOMException

INDEX_SIZE_ERR: Raised if the specified offset is negative or greater than the number of 16-bit units in data, or if the specified count is negative.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

Interface Attr

The Attr interface represents an attribute in an Element object. Typically the allowable values for the attribute are defined in a document type definition.

Attr objects inherit the Node interface, but since they are not actually child nodes of the element they describe, the DOM does not consider them part of the document tree. Thus, the Node attributes parentNode, previousSibling, and nextSibling have a null value for Attr objects. The DOM takes the view that attributes are properties of elements rather than having a separate identity from the elements they are associated with; this should make it more efficient to implement such features as default attributes associated with all elements of a given type. Furthermore, Attr nodes may not be immediate children of a DocumentFragment. However, they can be associated with Element nodes contained within a DocumentFragment. In short, users and implementors of the DOM need to be aware that Attr nodes have some things in common with other objects inheriting the Node interface, but they also are quite distinct.

The attribute's effective value is determined as follows: if this attribute has been explicitly assigned any value, that value is the attribute's effective value; otherwise, if there is a declaration for this attribute, and that declaration includes a default value, then that default value is the attribute's effective value; otherwise, the attribute does not exist on this element in the structure model until it has been explicitly added. Note that the nodeValue attribute on the Attr instance can also be used to retrieve the string version of the attribute's value(s).

In XML, where the value of an attribute can contain entity references, the child nodes of the Attr node provide a representation in which entity references are not expanded. These child nodes may be either Text or EntityReference nodes. Because the attribute type may be unknown, there are no tokenized attribute values.


IDL Definition
interface Attr : Node {
  readonly attribute DOMString        name;
  readonly attribute boolean          specified;
           attribute DOMString        value;
                                        // raises(DOMException) on setting

  // Introduced in DOM Level 2:
  readonly attribute Element          ownerElement;
};

Attributes
name of type DOMString, readonly
Returns the name of this attribute.

specified of type boolean, readonly
If this attribute was explicitly given a value in the original document, this is true; otherwise, it is false. Note that the implementation is in charge of this attribute, not the user. If the user changes the value of the attribute (even if it ends up having the same value as the default value) then the specified flag is automatically flipped to true. To re-specify the attribute as the default value from the DTD, the user must delete the attribute. The implementation will then make a new attribute available with specified set to false and the default value (if one exists).
In summary:
  • If the attribute has an assigned value in the document then specified is true, and the value is the assigned value.
  • If the attribute has no assigned value in the document and has a default value in the DTD, then specified is false, and the value is the default value in the DTD.
  • If the attribute has no assigned value in the document and has a value of #IMPLIED in the DTD, then the attribute does not appear in the structure model of the document.

value of type DOMString
On retrieval, the value of the attribute is returned as a string. Character and general entity references are replaced with their values.
On setting, this creates a Text node with the unparsed contents of the string.
Exceptions on setting

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.

ownerElement of type Element, readonly, introduced in DOM Level 2
The Element node this attribute is attached to or null if this attribute is not in use.

Interface Element

By far the vast majority of objects (apart from text) that authors encounter when traversing a document are Element nodes. Assume the following XML document:

<elementExample id="demo">
  <subelement1/>
  <subelement2><subsubelement/></subelement2>
</elementExample>  

When represented using DOM, the top node is a Document node containing an Element node for "elementExample" which contains two child Element nodes, one for "subelement1" and one for "subelement2". "subelement1" contains no child nodes.

Elements may have attributes associated with them; since the Element interface inherits from Node, the generic Node interface attribute attributes may be used to retrieve the set of all attributes for an element. There are methods on the Element interface to retrieve either an Attr object by name or an attribute value by name. In XML, where an attribute value may contain entity references, an Attr object should be retrieved to examine the possibly fairly complex sub-tree representing the attribute value. On the other hand, in HTML, where all attributes have simple string values, methods to directly access an attribute value can safely be used as a convenience.


IDL Definition
interface Element : Node {
  readonly attribute DOMString        tagName;
  DOMString          getAttribute(in DOMString name);
  void               setAttribute(in DOMString name, 
                                  in DOMString value)
                                        raises(DOMException);
  void               removeAttribute(in DOMString name)
                                        raises(DOMException);
  Attr               getAttributeNode(in DOMString name);
  Attr               setAttributeNode(in Attr newAttr)
                                        raises(DOMException);
  Attr               removeAttributeNode(in Attr oldAttr)
                                        raises(DOMException);
  NodeList           getElementsByTagName(in DOMString name);
  void               normalize();
  // Introduced in DOM Level 2:
  DOMString          getAttributeNS(in DOMString namespaceURI, 
                                    in DOMString localName);
  // Introduced in DOM Level 2:
  void               setAttributeNS(in DOMString namespaceURI, 
                                    in DOMString localName, 
                                    in DOMString value)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  void               removeAttributeNS(in DOMString namespacURI, 
                                       in DOMString localName)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  Attr               getAttributeNodeNS(in DOMString namespaceURI, 
                                        in DOMString localName);
  // Introduced in DOM Level 2:
  Attr               setAttributeNodeNS(in Attr newAttr)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  NodeList           getElementsByTagNameNS(in DOMString namespaceURI, 
                                            in DOMString localName);
};

Attributes
tagName of type DOMString, readonly
The name of the element. For example, in:
<elementExample id="demo"> 
        ... 
</elementExample> ,
tagName has the value "elementExample". Note that this is case-preserving in XML, as are all of the operations of the DOM. The HTML DOM returns the tagName of an HTML element in the canonical uppercase form, regardless of the case in the source HTML document.

Methods
getAttribute
Retrieves an attribute value by name.
Parameters

DOMString

name

The name of the attribute to retrieve.

Return Value

DOMString

The Attr value as a string, or the empty string if that attribute does not have a specified or default value.

No Exceptions

setAttribute
Adds a new attribute. If an attribute with that name is already present in the element, its value is changed to be that of the value parameter. This value is a simple string, it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an Attr node plus any Text and EntityReference nodes, build the appropriate subtree, and use setAttributeNode to assign it as the value of an attribute.
Parameters

DOMString

name

The name of the attribute to create or alter.

DOMString

value

Value to set in string form.

Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

removeAttribute
Removes an attribute by name. If the removed attribute is known to have a default value, an attribute immediately appears containing the default value.
Parameters

DOMString

name

The name of the attribute to remove.

Exceptions

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

getAttributeNode
Retrieves an Attr node by name.
Parameters

DOMString

name

The name of the attribute to retrieve.

Return Value

Attr

The Attr node with the specified attribute name or null if there is no such attribute.

No Exceptions

setAttributeNode
Adds a new attribute. If an attribute with that name is already present in the element, it is replaced by the new one.
Parameters

Attr

newAttr

The Attr node to add to the attribute list.

Return Value

Attr

If the newAttr attribute replaces an existing attribute with the same name, the previously existing Attr node is returned, otherwise null is returned.

Exceptions

DOMException

WRONG_DOCUMENT_ERR: Raised if newAttr was created from a different document than the one that created the element.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

INUSE_ATTRIBUTE_ERR: Raised if newAttr is already an attribute of another Element object. The DOM user must explicitly clone Attr nodes to re-use them in other elements.

removeAttributeNode
Removes the specified attribute.
Parameters

Attr

oldAttr

The Attr node to remove from the attribute list. If the removed Attr has a default value it is immediately replaced.

Return Value

Attr

The Attr node that was removed.

Exceptions

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

NOT_FOUND_ERR: Raised if oldAttr is not an attribute of the element.

getElementsByTagName
Returns a NodeList of all descendant elements with a given tag name, in the order in which they would be encountered in a preorder traversal of the Element tree.
Parameters

DOMString

name

The name of the tag to match on. The special value "*" matches all tags.

Return Value

NodeList

A list of matching Element nodes.

No Exceptions

normalize
Puts all Text nodes in the full depth of the sub-tree underneath this Element into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separates Text nodes, i.e., there are no adjacent Text nodes. This can be used to ensure that the DOM view of a document is the same as if it were saved and re-loaded, and is useful when operations (such as XPointer lookups) that depend on a particular document tree structure are to be used.
No Parameters
No Return Value
No Exceptions

getAttributeNS introduced in DOM Level 2
Retrieves an attribute value by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the attribute to retrieve. When it is null or an empty string, this method behaves like getAttribute.

DOMString

localName

The local name of the attribute to retrieve.

Return Value

DOMString

The Attr value as a string, or an empty string if that attribute does not have a specified or default value.

No Exceptions

setAttributeNS introduced in DOM Level 2
Adds a new attribute. If an attribute with that local name and namespace URI is already present in the element, its value is changed to be that of the value parameter. This value is a simple string, it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an Attr node plus any Text and EntityReference nodes, build the appropriate subtree, and use setAttributeNodeNS or setAttributeNode to assign it as the value of an attribute. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the attribute to create or alter. When it is null or an empty string, this method behaves like getAttribute.

DOMString

localName

The local name of the attribute to create or alter.

DOMString

value

The value to set in string form.

Exceptions

DOMException

INVALID_CHARACTER_ERR: Raised if the specified name contains an invalid character.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

removeAttributeNS introduced in DOM Level 2
Removes an attribute by local name and namespace URI. If the removed attribute has a default value it is immediately replaced. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespacURI

The namespace URI of the attribute to remove. When it is null or an empty string, this method behaves like removeAttribute.

DOMString

localName

The local name of the attribute to remove.

Exceptions

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

No Return Value

getAttributeNodeNS introduced in DOM Level 2
Retrieves an Attr node by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the attribute to retrieve. When it is null or an empty string, this method behaves like getAttributeNode.

DOMString

localName

The local name of the attribute to retrieve.

Return Value

Attr

The Attr node with the specified attribute local name and namespace URI or null if there is no such attribute.

No Exceptions

setAttributeNodeNS introduced in DOM Level 2
Adds a new attribute. If an attribute with that local name and namespace URI is already present in the element, it is replaced by the new one. HTML-only DOM implementations do not need to implement this method.
Parameters

Attr

newAttr

The Attr node to add to the attribute list. When the node has no namespaceURI, this method behaves like setAttributeNode.

Return Value

Attr

If the newAttr attribute replaces an existing attribute with the same local name and namespace URI, the previously existing Attr node is returned, otherwise null is returned.

Exceptions

DOMException

WRONG_DOCUMENT_ERR: Raised if newAttr was created from a different document than the one that created the element.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

INUSE_ATTRIBUTE_ERR: Raised if newAttr is already an attribute of another ElementNS object. The DOM user must explicitly clone Attr nodes to re-use them in other elements.

getElementsByTagNameNS introduced in DOM Level 2
Returns a NodeList of all the Elements with a given local name and namespace URI in the order in which they would be encountered in a preorder traversal of the Document tree, starting from this node. HTML-only DOM implementations do not need to implement this method.
Parameters

DOMString

namespaceURI

The namespace URI of the elements to match on. The special value "*" matches all namespaces. When it is null or an empty string, this method behaves like getElementsByTagName.

DOMString

localName

The local name of the elements to match on. The special value "*" matches all local names.

Return Value

NodeList

A new NodeList object containing all the matched Elements.

No Exceptions

Interface Text

The Text interface inherits from CharacterData and represents the textual content (termed character data in XML) of an Element or Attr. If there is no markup inside an element's content, the text is contained in a single object implementing the Text interface that is the only child of the element. If there is markup, it is parsed into a list of elements and Text nodes that form the list of children of the element.

When a document is first made available via the DOM, there is only one Text node for each block of text. Users may create adjacent Text nodes that represent the contents of a given element without any intervening markup, but should be aware that there is no way to represent the separations between these nodes in XML or HTML, so they will not (in general) persist between DOM editing sessions. The normalize() method on Element merges any such adjacent Text objects into a single node for each block of text; this is recommended before employing operations that depend on a particular document structure, such as navigation with XPointers.


IDL Definition
interface Text : CharacterData {
  Text               splitText(in unsigned long offset)
                                        raises(DOMException);
};

Methods
splitText
Breaks this Text node into two Text nodes at the specified offset, keeping both in the tree as siblings. This node then only contains all the content up to the offset point. And a new Text node, which is inserted as the next sibling of this node, contains all the content at and after the offset point.
Parameters

unsigned long

offset

The 16-bit unit offset at which to split, starting from 0.

Return Value

Text

The new Text node.

Exceptions

DOMException

INDEX_SIZE_ERR: Raised if the specified offset is negative or greater than the number of 16-bit units in data.

NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

Interface Comment

This interface inherits from CharacterData and represents the content of a comment, i.e., all the characters between the starting '<!--' and ending '-->'. Note that this is the definition of a comment in XML, and, in practice, HTML, although some HTML tools may implement the full SGML comment structure.


IDL Definition
interface Comment : CharacterData {
};

1.3. Extended Interfaces

The interfaces defined here form part of the DOM Core specification, but objects that expose these interfaces will never be encountered in a DOM implementation that deals only with HTML. As such, HTML-only DOM implementations do not need to have objects that implement these interfaces.

A DOM application can use the hasFeature method of the DOMImplementation interface to determine whether they are supported or not. The feature string for all the interfaces listed in this section is "XML".

Interface CDATASection

CDATA sections are used to escape blocks of text containing characters that would otherwise be regarded as markup. The only delimiter that is recognized in a CDATA section is the "]]>" string that ends the CDATA section. CDATA sections can not be nested. The primary purpose is for including material such as XML fragments, without needing to escape all the delimiters.

The DOMString attribute of the Text node holds the text that is contained by the CDATA section. Note that this may contain characters that need to be escaped outside of CDATA sections and that, depending on the character encoding ("charset") chosen for serialization, it may be impossible to write out some characters as part of a CDATA section.

The CDATASection interface inherits from the CharacterData interface through the Text interface. Adjacent CDATASections nodes are not merged by use of the normalize method of the Element interface.


IDL Definition
interface CDATASection : Text {
};

Interface DocumentType

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 scheme efforts on DTD representation are not clearly understood as of this writing.

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


IDL Definition
interface DocumentType : Node {
  readonly attribute DOMString        name;
  readonly attribute NamedNodeMap     entities;
  readonly attribute NamedNodeMap     notations;
  // Introduced in DOM Level 2:
  readonly attribute DOMString        publicID;
  // Introduced in DOM Level 2:
  readonly attribute DOMString        systemID;
};

Attributes
name of type DOMString, readonly
The name of DTD; i.e., the name immediately following the DOCTYPE keyword.

entities of type NamedNodeMap, readonly
A NamedNodeMap containing the general entities, both external and internal, declared in the DTD. Duplicates are discarded. For example in:
<!DOCTYPE ex SYSTEM "ex.dtd" [
  <!ENTITY foo "foo">
  <!ENTITY bar "bar">
  <!ENTITY % baz "baz">
]>
<ex/>
the interface provides access to foo and bar but not 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.

notations of type NamedNodeMap, readonly
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.

publicID of type DOMString, readonly, introduced in DOM Level 2
The public identifier of this document type.

systemID of type DOMString, readonly, introduced in DOM Level 2
The system identifier of this document type.

Interface Notation

This interface represents a notation declared in the DTD. A notation either declares, by name, the format of an unparsed entity (see section 4.7 of the XML 1.0 specification), or is used for formal declaration of Processing Instruction targets (see section 2.6 of the XML 1.0 specification). The nodeName attribute inherited from Node is set to the declared name of the notation.

The DOM Level 1 does not support editing Notation nodes; they are therefore readonly.

A Notation node does not have any parent.


IDL Definition
interface Notation : Node {
  readonly attribute DOMString        publicId;
  readonly attribute DOMString        systemId;
};

Attributes
publicId of type DOMString, readonly
The public identifier of this notation. If the public identifier was not specified, this is null.

systemId of type DOMString, readonly
The system identifier of this notation. If the system identifier was not specified, this is null.

Interface Entity

This interface represents an entity, either parsed or unparsed, in an XML document. Note that this models the entity itself not the entity declaration. Entity declaration modeling has been left for a later Level of the DOM specification.

The nodeName attribute that is inherited from Node contains the name of the entity.

An XML processor may choose to completely expand entities before the structure model is passed to the DOM; in this case there will be no EntityReference nodes in the document tree.

XML does not mandate that a non-validating XML processor read and process entity declarations made in the external subset or declared in external parameter entities. This means that parsed entities declared in the external subset need not be expanded by some classes of applications, and that the replacement value of the entity may not be available. When the replacement value is available, the corresponding Entity node's child list represents the structure of that replacement text. Otherwise, the child list is empty.

The resolution of the children of the Entity (the replacement value) may be lazily evaluated; actions by the user (such as calling the childNodes method on the Entity Node) are assumed to trigger the evaluation.

The DOM Level 2 does not support editing Entity nodes; if a user wants to make changes to the contents of an Entity, every related EntityReference node has to be replaced in the structure model by a clone of the Entity's contents, and then the desired changes must be made to each of those clones instead. All the descendants of an Entity node are readonly.

An Entity node does not have any parent.


IDL Definition
interface Entity : Node {
  readonly attribute DOMString        publicId;
  readonly attribute DOMString        systemId;
  readonly attribute DOMString        notationName;
};

Attributes
publicId of type DOMString, readonly
The public identifier associated with the entity, if specified. If the public identifier was not specified, this is null.

systemId of type DOMString, readonly
The system identifier associated with the entity, if specified. If the system identifier was not specified, this is null.

notationName of type DOMString, readonly
For unparsed entities, the name of the notation for the entity. For parsed entities, this is null.

Interface EntityReference

EntityReference objects may be inserted into the structure model when an entity reference is in the source document, or when the user wishes to insert an entity reference. Note that character references and references to predefined entities are considered to be expanded by the HTML or XML processor so that characters are represented by their Unicode equivalent rather than by an entity reference. Moreover, the XML processor may completely expand references to entities while building the structure model, instead of providing EntityReference objects. If it does provide such objects, then for a given EntityReference node, it may be that there is no Entity node representing the referenced entity; but if such an Entity exists, then the child list of the EntityReference node is the same as that of the Entity node. As with the Entity node, all descendants of the EntityReference are readonly.

The resolution of the children of the EntityReference (the replacement value of the referenced Entity) may be lazily evaluated; actions by the user (such as calling the childNodes method on the EntityReference node) are assumed to trigger the evaluation.


IDL Definition
interface EntityReference : Node {
};

Interface ProcessingInstruction

The ProcessingInstruction interface represents a "processing instruction", used in XML as a way to keep processor-specific information in the text of the document.


IDL Definition
interface ProcessingInstruction : Node {
  readonly attribute DOMString        target;
           attribute DOMString        data;
                                        // raises(DOMException) on setting

};

Attributes
target of type DOMString, readonly
The target of this processing instruction. XML defines this as being the first token following the markup that begins the processing instruction.

data of type DOMString
The content of this processing instruction. This is from the first non white space character after the target to the character immediately preceding the ?>.
Exceptions on setting

DOMException

NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.


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