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This section defines a minimal set of objects andinterfaces for accessing and manipulating document objects.The functionality specified in this section (theCore functionality) should be sufficient to allowsoftware developers and web script authors to access andmanipulate parsed HTML and XML content inside conformingproducts. The DOM Core API also allows populationof aDocument object using only DOM API calls; creating the skeletonDocument and saving it persistently is left to the product that implements the DOM API.
The DOM presents documents as a hierarchy ofNodeobjects that also implement other, more specialized interfaces. Sometypes of nodes may have child nodes of various types, and others areleaf nodes that cannot have anything below them in the documentstructure. The node types, and which node types they may have aschildren, are as follows:
Document --Element (maximum of one),ProcessingInstruction,Comment,DocumentTypeDocumentFragment --Element,ProcessingInstruction,Comment,Text,CDATASection,EntityReferenceDocumentType -- no childrenEntityReference --Element,ProcessingInstruction,Comment,Text,CDATASection,EntityReferenceElement --Element,Text,Comment,ProcessingInstruction,CDATASection,EntityReferenceAttr --Text,EntityReferenceProcessingInstruction -- no childrenComment -- no childrenText -- no childrenCDATASection -- no childrenEntity --Element,ProcessingInstruction,Comment,Text,CDATASection,EntityReferenceNotation -- no childrenThe DOM also specifies aNodeList interface to handleordered lists ofNodes, such as the children of aNode, or the elements returned by theElement.getElementsByTagName method, and also aNamedNodeMap interface to handle unordered sets of nodesreferenced by their name attribute, such as the attributes of anElement.NodeLists andNamedNodeMaps in the DOM are "live", that is, changes tothe underlying document structure are reflected in all relevantNodeLists andNamedNodeMaps. For example, ifa DOM user gets aNodeList object containing the childrenof anElement, then subsequently adds more children tothat element (or removes children, or modifies them), those changes areautomatically reflected in theNodeList without furtheraction on the user's part. Likewise changes to aNode inthe tree are reflected in all references to thatNode inNodeLists andNamedNodeMaps.
Most of the APIs defined by this specification areinterfaces rather than classes. That means that an actual implementation need only expose methods with the defined names and specified operation, not actuallyimplement classes that correspond directly to the interfaces.This allows the DOM APIs to be implemented as a thin veneer on topof 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 relationshipto the DOM interfaces. The conventional solution to this inobject-oriented design is to definefactory methodsthat create instances of objects that implement the variousinterfaces. In the DOM Level 1, objects implementing someinterface "X" are created by a "createX()" method on theDocument interface; this is because all DOM objects livein the context of a specific Document.
The DOM Level 1 API doesnot define a standardway to createDOMImplementation orDocumentobjects; actual DOM implementations must providesome proprietary way of bootstrapping these DOM interfaces, andthen all other objects can be built from the Create methods onDocument (or by various other convenience methods).
The Core DOM APIs are designed to be compatible with a widerange of languages, including both general-user scripting languages andthe more challenging languages used mostly by professional programmers.Thus, the DOMAPIs need to operate across a variety of memory managementphilosophies, from language platforms that do not expose memorymanagement to the user at all, through those (notably Java) that provide explicit constructors but provide an automatic garbagecollection mechanism to automatically reclaim unused memory,to those (especially C/C++) that generally require theprogrammer to explicitly allocate object memory, track whereit is used, and explicitly free it for re-use. To ensure aconsistent API across these platforms, the DOM does notaddress memory management issues at all, but instead leaves these for theimplementation. Neither of the explicit language bindingsdevised by the DOM Working Group (for ECMAScript and Java)require any memory management methods, but DOM bindings forother languages (especially C or C++) probably will requiresuch support. These extensions will be the responsibility ofthose adapting the DOM API to a specific language, not the DOMWG.
While it wouldbe nice to have attribute and method names that are short,informative, internally consistent, and familiar to users ofsimilar APIs, the names also should not clash with the namesin legacy APIs supported by DOM implementations.Furthermore, both OMG IDL andECMAScript havesignificant limitations in their ability to disambiguate namesfrom different namespaces that makes it difficult to avoid namingconflicts with short, familiar names. So, DOM names tend to belong and quite descriptive in order to be unique across allenvironments.
The Working Group has also attempted to be internallyconsistent in its use of various terms, even though these maynot be common distinctions in other APIs. For example, we usethe method name "remove" when the method changes thestructural model, and the method name "delete" when the methodgets rid of something inside the structure model. The thingthat is deleted is not returned. The thing that is removed maybe returned, when it makes sense to return it.
The DOM Core APIs present two somewhat different sets ofinterfaces to an XML/HTML document; one presenting an "objectoriented" approach with a hierarchy of inheritance, and a"simplified" view that allows all manipulation to be done viatheNode interface without requiring casts (inJava and other C-like languages) or query interface calls inCOM environments. These operations are fairly expensive in Java andCOM, and the DOM may be used in performance-criticalenvironments, so we allow significant functionality using just theNode interface. Because many other users will find theinheritance hierarchy easier to understand than the"everything is aNode" approach to the DOM, we alsosupport the full higher-level interfaces for those who prefer a moreobject-oriented API.
In practice, this means that there is a certain amount ofredundancy in the API. The Working Group considers the"inheritance" approach the primary view of the API, and thefull set of functionality onNode to be "extra"functionality that users may employ, but that does not eliminatethe need for methods on other interfaces that anobject-oriented analysis would dictate. (Of course, when theO-O analysis yields an attribute or method that is identical to one on theNode interface, we don'tspecify a completely redundant one). Thus, even though thereis a genericnodeName attribute on theNodeinterface, there is still atagName attribute on theElement interface; these two attributes mustcontain the same value, but the Working Group considers itworthwhile to support both, given the different constituenciesthe DOM API must satisfy.
DOMString typeTo ensure interoperability, the DOM specifies theDOMString type as follows:
DOMString is a sequence of 16-bit quantities. This may be expressed in IDL terms as:typedef sequence<unsigned short> DOMString;
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-4. A single numeric character reference in a source document may therefore in some cases correspond to two array positions in aDOMString (a high surrogate and a low surrogate).Note:Even though the DOM defines the name of the string type to beDOMString, bindings may used different names. For, example for Java,DOMString is bound to theString type because it also uses UTF-16 as itsencoding.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.The DOM has many interfaces that imply string matching. HTML processors generally assume an uppercase (less often, lowercase) normalization of names for such things aselements, while XML is explicitly case sensitive. For thepurposes of the DOM, string matching takes place on a charactercode by character code basis, on the 16 bit value of aDOMString. As such, the DOM assumes that anynormalizations will take place in the processor,before the DOM structures are built.
This then raises the issue of exactly what normalizationsoccur. The W3C I18N working group is in the process ofdefining exactly which normalizations are necessary for applicationsimplementing the DOM.
The interfaces within this section are consideredfundamental, and must be fully implemented by all conforming implementations of the DOM, including all HTML DOM implementations.
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 usingNodeList.
Implementations may raise other exceptions under other circumstances. For example, implementations may raise an implementation-dependent exception if anull 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.
exception DOMException { unsigned short code;};// ExceptionCodeconst 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;An integer indicating the type of error generated.
| 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 |
TheDOMImplementation interface provides a number of methods for performing operations that are independent of any particular instance of the document object model.
The DOM Level 1 does not specify a way of creating a document instance, and hence document creation is an operation specific to an implementation. Future Levels of the DOM specification are expected to provide methods for creating documents directly.
interface DOMImplementation { boolean hasFeature(in DOMString feature, in DOMString version);};hasFeaturefeature | The package name of the feature to test. In Level 1, the legal values are "HTML" and"XML" (case-insensitive). | |
version | This is the version number of the package name totest. In Level 1, this is the string "1.0".If the version is not specified, supporting any version of the feature will cause the method to return |
true if the feature is implemented in the specifiedversion,false otherwise.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 aDocument object could fulfil this role, aDocument 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 anotherNode -- may takeDocumentFragment objects as arguments; this results in all the child nodes of theDocumentFragment being moved to the child list of this node.
The children of aDocumentFragment 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, aDocumentFragment might have only one child and that child node could be aText node. Such a structure model represents neither an HTML document nor a well-formed XML document.
When aDocumentFragment is inserted into aDocument (or indeed any otherNode that may take children) the children of theDocumentFragment and not theDocumentFragment itself are inserted into theNode. This makes theDocumentFragment very useful when the user wishes to create nodes that are siblings; theDocumentFragment acts as the parent of these nodes so that the user can use the standard methods from theNode interface, such asinsertBefore() andappendChild().
interface DocumentFragment : Node {};TheDocument 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 aDocument, theDocument interface also contains the factory methods needed to create these objects. TheNode objects created have aownerDocument attribute which associates them with theDocument within whose context they were created.
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);};doctypeDocumentType)associated with this document. For HTML documents as well as XML documents without adocument type declaration this returnsnull. The DOM Level 1 does not support editing the Document Type Declaration, thereforedocType cannot be altered in any way.implementationDOMImplementation object that handles thisdocument. A DOM application may use objects from multiple implementations.documentElementcreateElementtagName | The name of the element type to instantiate. For XML, this is case-sensitive. For HTML, the |
Element object.DOMExceptionINVALID_CHARACTER_ERR: Raised if the specified name containsan invalid character.
createDocumentFragmentDocumentFragment object.DocumentFragment.createTextNodecreateCommentcreateCDATASectionCDATASection node whose value isthe specified string.data | The data for the |
CDATASection object.DOMExceptionNOT_SUPPORTED_ERR: Raised if this document is an HTMLdocument.
createProcessingInstructionProcessingInstruction node giventhe specified name and data strings.target | The target part of the processing instruction. | |
data | The data for the node. |
ProcessingInstruction object.DOMExceptionINVALID_CHARACTER_ERR: Raised if an invalid character is specified.
NOT_SUPPORTED_ERR: Raised if this document is an HTML document.
createAttributeAttr of the given name.Note that theAttr instancecan then be set on anElement using thesetAttribute method.name | The name of the attribute. |
Attr object.DOMExceptionINVALID_CHARACTER_ERR: Raised if the specified name containsan invalid character.
createEntityReferencename | The name of the entity to reference. |
EntityReference object.DOMExceptionINVALID_CHARACTER_ERR: Raised if the specified name containsan invalid character.
NOT_SUPPORTED_ERR: Raised if this document is an HTML document.
getElementsByTagNameTheNode interface is the primary datatype for the entire Document Object Model. It represents a single node in the document tree. While all objects implementing theNode interface expose methods for dealing with children, not all objects implementing theNode interface may have children. For example,Text nodes may not have children, and adding children to such nodes results in aDOMException being raised.
The attributesnodeName,nodeValue andattributes 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 specificnodeType (e.g.,nodeValue for an Element orattributes for a Comment), this returnsnull. Note that the specialized interfaces may containadditional and more convenient mechanisms to get and set the relevantinformation.
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; 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);};An integer indicating which type of node this is.
| ELEMENT_NODE | The node is a |
| ATTRIBUTE_NODE | The node is an |
| TEXT_NODE | The node is a |
| CDATA_SECTION_NODE | The node is a |
| ENTITY_REFERENCE_NODE | The node is an |
| ENTITY_NODE | The node is an |
| PROCESSING_INSTRUCTION_NODE | The node is a |
| COMMENT_NODE | The node is a |
| DOCUMENT_NODE | The node is a |
| DOCUMENT_TYPE_NODE | The node is a |
| DOCUMENT_FRAGMENT_NODE | The node is a |
| NOTATION_NODE | The node is a |
The values ofnodeName,nodeValue, andattributes vary according to the node type as follows:
| nodeName | nodeValue | attributes | |
| Element | tagName | null | NamedNodeMap |
| Attr | name of attribute | value of attribute | null |
| Text | #text | content of the text node | null |
| CDATASection | #cdata-section | content of the CDATA Section | null |
| EntityReference | name of entity referenced | null | null |
| Entity | entity name | null | null |
| ProcessingInstruction | target | entire content excluding the target | null |
| Comment | #comment | content of the comment | null |
| Document | #document | null | null |
| DocumentType | document type name | null | null |
| DocumentFragment | #document-fragment | null | null |
| Notation | notation name | null | null |
nodeNamenodeValueDOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
DOMExceptionDOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in aDOMString variable on the implementation platform.
nodeTypeparentNodeDocument,DocumentFragment, andAttr may have a parent. However, if anode has just been created and not yet added to the tree, or if it has been removed from the tree, this isnull.childNodesNodeList that contains allchildren of this node. If there are no children, this is aNodeList containing no nodes. The content of thereturnedNodeList is "live" in thesense that, for instance, changes to the children of the node objectthat itwas created from are immediately reflected in the nodesreturned by theNodeList accessors; it is not astatic snapshot of the content of the node. This is true for everyNodeList, including the ones returned by thegetElementsByTagName method.firstChildnull.lastChildnull.previousSiblingnull.nextSiblingnull.attributesNamedNodeMap containing theattributes of this node (if it is anElement) ornull otherwise.ownerDocumentDocument object associated with this node. Thisis also theDocument object used to create new nodes. Whenthis node is aDocument this isnull.insertBeforenewChild before theexisting child noderefChild. IfrefChild isnull, insertnewChild at the end of the list of children.IfnewChild is aDocumentFragment object, all of its children are inserted, in the same order, beforerefChild. If thenewChild is already in thetree, it is first removed.
newChild | The node to insert. | |
refChild | The reference node, i.e., the node before whichthe new node must be inserted. |
DOMExceptionHIERARCHY_REQUEST_ERR: Raised if this node is of a typethat does not allow children of the type of thenewChildnode, or if the node to insert is one of this node's ancestors.
WRONG_DOCUMENT_ERR: Raised ifnewChild was created froma different document than the one that created this node.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised ifrefChild is not a child of this node.
replaceChildoldChild withnewChild in the list of children, and returns theoldChild node. If thenewChild is already inthe tree, it is first removed.newChild | The new node to put in the child list. | |
oldChild | The node being replaced in the list. |
DOMExceptionHIERARCHY_REQUEST_ERR: Raised if this node is of a typethat does not allow children of the type of thenewChildnode, or it the node to put in is one of this node's ancestors.
WRONG_DOCUMENT_ERR: Raised ifnewChild was created froma different document than the one that created this node.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised ifoldChild is not achild of this node.
removeChildoldChild fromthe list of children, and returns it.oldChild | The node being removed. |
DOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised if this node isreadonly.
NOT_FOUND_ERR: Raised ifoldChild is not a child of this node.
appendChildnewChild to the end of the list ofchildren of this node. If thenewChild is already in thetree, it is first removed.newChild | The node to add. If it is a |
DOMExceptionHIERARCHY_REQUEST_ERR: Raised if this node is of a typethat does not allow children of the type of thenewChildnode, or if the node to append is one of this node's ancestors.
WRONG_DOCUMENT_ERR: Raised ifnewChild was created froma different document than the one that created this node.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
hasChildNodestrue if the node has any children,false if the node has no children.cloneNodeparentNode returnsnull.).Cloning anElement copiesall 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 childText node. Cloning any other type ofnode simply returns a copy of this node.
deep | If |
TheNodeList interface provides the abstraction of an ordered collection of nodes, without defining or constraining how this collection is implemented.
The items in theNodeList are accessible via an integral index, starting from 0.
interface NodeList { Node item(in unsigned long index); readonly attribute unsigned long length;};itemindexth item in the collection.Ifindex is greater than or equal to the numberof nodes in the list, this returnsnull.index | Index into the collection. |
indexth position in theNodeList, ornull if that is not a valid index.lengthlength-1 inclusive.Objects implementing theNamedNodeMap interface are used to represent collections of nodes that can be accessed by name. Note thatNamedNodeMap does not inherit fromNodeList;NamedNodeMaps are not maintained in any particular order. Objects contained in an object implementingNamedNodeMap may also be accessed by an ordinal index, but this is simply to allow convenient enumeration of the contents of aNamedNodeMap, and does not imply that the DOM specifies an order to these Nodes.
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;};getNamedItemname | Name of a node to retrieve. |
Node (of any type) with the specified name, ornull if the specified name did not identify any node in the map.setNamedItemnodeName attribute.As thenodeName attribute is used toderive the name which the node must be stored under, multiplenodes of certain types (those that have a "special" stringvalue) cannot be stored as the names would clash. This is seenas preferable to allowing nodes to be aliased.
arg | A node to store in a named node map. The node willlater be accessible using the value of the |
Node replaces an existing node with the same name the previously existingNode is returned, otherwisenull is returned.DOMExceptionWRONG_DOCUMENT_ERR: Raised ifarg was created from a differentdocument than the one that created theNamedNodeMap.
NO_MODIFICATION_ALLOWED_ERR: Raised if thisNamedNodeMap is readonly.
INUSE_ATTRIBUTE_ERR: Raised ifarg is anAttrthat is already an attribute of anotherElement object. TheDOM user must explicitly cloneAttrnodes to re-use them in other elements.
removeNamedItemAttr with a default value it is immediately replaced.name | The name of a node to remove. |
null if no node with such a name exists.DOMExceptionNOT_FOUND_ERR: Raised if there is no node namedname in the map.
itemindexth item in the map.Ifindex is greater than or equal to the numberof nodes in the map, this returnsnull.index | Index into the map. |
indexth position in theNamedNodeMap, ornull if that is not a valid index.lengthlength-1 inclusive.TheCharacterData interface extends Node with a set of attributesand methods for accessing character data in the DOM. For clarity this set is definedhere rather than on each object that uses these attributes and methods. No DOM objects correspond directly toCharacterData, thoughText andothers do inherit the interface from it. Alloffsets inthis interface start from 0.
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);};dataCharacterData node. However, implementation limits may mean that the entirety of a node's data may not fit into a singleDOMString. In such cases, the user may callsubstringData to retrieve the data in appropriately sizedpieces.DOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
DOMExceptionDOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in aDOMString variable on the implementation platform.
lengthdata and thesubstringData method below. This may have the value zero, i.e.,CharacterData nodes may be empty.substringDataoffset | Start offset of substring to extract. | |
count | The number of characters to extract. |
offset andcount exceeds thelength, then all characters to the end of the data are returned.DOMExceptionINDEX_SIZE_ERR: Raised if the specified offset is negative orgreater than the number of characters indata, or if the specifiedcount is negative.
DOMSTRING_SIZE_ERR: Raised if the specified range of text doesnot fit into aDOMString.
appendDatadata provides access to the concatenation ofdata and theDOMString specified.arg | The |
DOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised if this node isreadonly.
insertDataoffset | The character offset at which to insert. | |
arg | The |
DOMExceptionINDEX_SIZE_ERR: Raised if the specified offset is negative orgreater than the number of characters indata.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
deleteDatadata andlength reflect the change.offset | The offset from which to remove characters. | |
count | The number of characters to delete. If the sum of |
DOMExceptionINDEX_SIZE_ERR: Raised if the specified offset is negative orgreater than the number of characters indata, or if the specifiedcount is negative.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
replaceDataoffset | The offset from which to start replacing. | |
count | The number of characters to replace. If the sum of | |
arg | The |
DOMExceptionINDEX_SIZE_ERR: Raised if the specified offset is negative orgreater than the number of characters indata, or if the specifiedcount is negative.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
TheAttr interface represents an attribute in anElement object.Typically the allowable values for the attribute are defined in a documenttype definition.
Attr objects inherit theNode 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, theNode attributesparentNode,previousSibling, andnextSibling have a null value forAttr 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 aDocumentFragment. However, they can be associated withElement nodes contained within aDocumentFragment. In short, users and implementors of the DOM need to be aware thatAttr nodes have some things in common with other objects inheriting theNode 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 thenodeValue attribute on theAttr 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 theAttr node provide a representation in which entity references are not expanded. These child nodes may be eitherText orEntityReference nodes. Because the attribute type may be unknown, there are no tokenized attribute values.
interface Attr : Node { readonly attribute DOMString name; readonly attribute boolean specified; attribute DOMString value;};namespecifiedtrue; otherwise, it isfalse. 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 thespecified flag is automatically flipped totrue. 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 withspecified set tofalse and the default value (if one exists).In summary:
specified istrue, and the value is the assigned value.specified isfalse, and the value is the default value in the DTD.valueOn setting, this creates aText node with the unparsedcontents of the string.
By far the vast majority of objects (apart from text) that authors encounter when traversing a document areElement nodes. Assume the following XML document:
<elementExample> <subelement1/> <subelement2><subsubelement/></subelement2></elementExample>
When represented using DOM, the top node is anElement node for "elementExample", which contains two childElement nodes, one for "subelement1" and one for "subelement2". "subelement1" contains no child nodes.
Elements may have attributes associated with them; since theElement interface inherits fromNode, the genericNode interface methodgetAttributes may be used to retrieve the set of all attributes for an element. There are methods on theElement interface to retrieve either anAttr object by name or an attribute value by name. In XML, where an attribute value may contain entity references, anAttr 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.
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();};tagName<elementExample> ... </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 thetagName of an HTML element in the canonical uppercase form, regardless of the case in the source HTML document.getAttributename | The name of the attribute to retrieve. |
Attr value as a string, or the empty string if that attribute does not have a specified or default value.setAttributeAttr node plus anyText andEntityReference nodes, build the appropriate subtree, and usesetAttributeNode to assign it as the value of an attribute.name | The name of the attribute to create or alter. | |
value | Value to set in string form. |
DOMExceptionINVALID_CHARACTER_ERR: Raised if the specified name containsan invalid character.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
removeAttributename | The name of the attribute to remove. |
DOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised if this node isreadonly.
getAttributeNodesetAttributeNodenewAttr | The |
newAttr attribute replacesan existing attribute with the same name, the previously existingAttr node is returned, otherwisenull is returned.DOMExceptionWRONG_DOCUMENT_ERR: Raised ifnewAttr wascreated from a different document than the one that created theelement.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
INUSE_ATTRIBUTE_ERR: Raised ifnewAttr is alreadyan attribute of anotherElement object. TheDOM user must explicitly cloneAttrnodes to re-use them in other elements.
removeAttributeNodeoldAttr | The |
Attr node that was removed.DOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised if this node isreadonly.
NOT_FOUND_ERR: Raised ifoldAttr is not an attribute ofthe element.
getElementsByTagNameNodeList of all descendant elements with agiven tag name, in the order in which they would be encountered in apreorder traversal of theElement tree.name | The name of the tag to match on. The special value "*" matches all tags. |
Element nodes.normalizeText nodes in the full depth of the sub-tree underneath thisElement into a "normal" formwhere only markup (e.g., tags, comments, processing instructions, CDATAsections, and entity references) separatesText nodes,i.e., there are no adjacentText nodes. This can be usedto ensure that the DOM view of a document is the same as if it weresaved and re-loaded, and is useful when operations (such as XPointerlookups) that depend on a particular document tree structure are to beused.TheText interface represents the textual content (termedcharacter data in XML) of anElement orAttr. If there is no markup inside an element's content, the text is contained in a single object implementing theText interface that is the only child of the element. If there is markup, it is parsed into a list of elements andText nodes that form the list of children of the element.
When a document is first made available via the DOM, there is only oneText node for each block of text. Users may create adjacentText 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. Thenormalize() method onElement merges any such adjacentText 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 withXPointers.
interface Text : CharacterData { Text splitText(in unsigned long offset) raises(DOMException);};splitTextText node into two Text nodes at thespecified offset, keeping both in the tree as siblings. This node thenonly contains all the content up to theoffset point. Anda newText node, which is inserted as the next sibling of this node, contains all the content at and after theoffset point.offset | The offset at which to split, starting from 0. |
Text node.DOMExceptionINDEX_SIZE_ERR: Raised if the specified offset is negative orgreater than the number of characters indata.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
This 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.
interface Comment : CharacterData {};The interfaces defined here form part of the DOM Level 1 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.
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.
TheDOMString attribute of theText node holds the text that is contained by the CDATA section. Note that thismay 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.
TheCDATASection interface inherits theCharacterData interface through theText interface. AdjacentCDATASections nodes are not merged by use of the Element.normalize() method.
interface CDATASection : Text {};EachDocument has adoctype attribute whose value is eithernull or aDocumentType object. TheDocumentType interface in the DOM Level 1 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 1 doesn't support editingDocumentType nodes.
interface DocumentType : Node { readonly attribute DOMString name; readonly attribute NamedNodeMap entities; readonly attribute NamedNodeMap notations;};nameDOCTYPE keyword.entitiesNamedNodeMap containing the general entities, bothexternal 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 andbar but notbaz. Every node in this mapalso implements theEntity interface.The DOM Level 1 does not support editing entities, thereforeentities cannot be altered in any way.
notationsNamedNodeMap containing thenotations declared in the DTD. Duplicates are discarded. Every node inthis map also implements theNotation interface.The DOM Level 1 does not support editing notations, thereforenotations cannot be altered in any way.
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). ThenodeName attribute inherited fromNode is set to the declared name of the notation.
The DOM Level 1 does not support editingNotation nodes; they are therefore readonly.
ANotation node does not have any parent.
interface Notation : Node { readonly attribute DOMString publicId; readonly attribute DOMString systemId;};publicIdnull.systemIdnull.This interface represents an entity, either parsed or unparsed, in an XML document. Note that this models the entity itselfnot the entity declaration.Entity declaration modeling has been left for a later Level of the DOM specification.
ThenodeName attribute that is inherited fromNode 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 noEntityReference 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 correspondingEntity node's child list represents the structure of that replacement text. Otherwise, the child list is empty.
The resolution of the children of theEntity (the replacement value) may be lazily evaluated; actions by the user (such as calling thechildNodes method on theEntity Node) are assumed to trigger the evaluation.
The DOM Level 1 does not support editingEntity nodes; if a user wants to make changes to the contents of anEntity, every relatedEntityReference node has to be replaced in the structure model by a clone of theEntity's contents, and then the desired changes must be made to each of those clones instead. All the descendants of anEntity node are readonly.
AnEntity node does not have any parent.
interface Entity : Node { readonly attribute DOMString publicId; readonly attribute DOMString systemId; readonly attribute DOMString notationName;};publicIdnull.systemIdnull.notationNamenull.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 providingEntityReference objects. If it does provide such objects, then for a givenEntityReference node, it may be that there is noEntity node representing the referenced entity; but if such anEntity exists, then the child list of theEntityReference node is the same as that of theEntity node. As with theEntity node, all descendants of theEntityReference are readonly.
The resolution of the children of theEntityReference (the replacement value of the referencedEntity) may be lazily evaluated; actions by the user (such as calling thechildNodes method on theEntityReference node) are assumed to trigger the evaluation.
interface EntityReference : Node {};TheProcessingInstruction interface represents a "processing instruction", used in XML as a way to keep processor-specific information in the text of the document.
interface ProcessingInstruction : Node { readonly attribute DOMString target; attribute DOMString data; // raises(DOMException) on setting};targetdata?>.DOMExceptionNO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.
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