Document Object Model (DOM) Level 2 Specification Version 1.0 W3C Candidate Recommendation 10 December, 1999 This version: http://www.w3.org/TR/1999/CR-DOM-Level-2-19991210 (PostScript file, PDF file, plain text, ZIP file) Latest version: http://www.w3.org/TR/DOM-Level-2 Previous versions: http://www.w3.org/TR/1999/WD-DOM-Level-2-19990923 http://www.w3.org/TR/1999/WD-DOM-Level-2-19990719 Editors: Lauren Wood, SoftQuad Software Inc., chair Arnaud Le Hors, W3C, staff contact (until October 1999) Vidur Apparao, Netscape Communications Corporation Laurence Cable, Sun Mike Champion, Arbortext and Software AG Joe Kesselman, IBM Philippe Le Hégaret, W3C, staff contact (from November 1999) Tom Pixley, Netscape Communications Corporation Jonathan Robie, Texcel Research and Software AG Peter Sharpe, SoftQuad Software Inc. Chris Wilson, Microsoft Copyright © 1999 W3C® (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply. ---------------------------------------------------------------------------- Abstract This specification defines the Document Object Model Level 2, a platform- and language-neutral interface that allows programs and scripts to dynamically access and update the content, structure and style of documents. The Document Object Model Level 2 builds on the Document Object Model Level 1. The DOM Level 2 is made of a set of core interfaces to create and manipulate the structure and contents of a document and a set of optional modules. These modules contain specialized interfaces dedicated to XML, HTML, an abstract view, generic stylesheets, Cascading Style Sheets, Events, traversing the document structure, and a Range object. ---------------------------------------------------------------------------- Status of this document This specification is now in the Candidate Recommendation phase. This means the specification is stable, and there will be a period to allow implementation of the specification. After this CR phase ends, on January 19, the specification will move into the Proposed Recommendation phase and it will be sent to the W3C membership for review. Comments on this document are invited and are to be sent to the public mailing list www-dom@w3.org. An archive is available at http://lists.w3.org/Archives/Public/www-dom/. Should this specification prove impossible or very difficult to implement, the necessary changes to make it implementable will be made. If this specification is possible to implement, the only changes which will be made to this specification are minor editorial changes and clarifications. This document has been produced as part of the W3C DOM Activity. The authors of this document are the DOM WG members. Different modules of the Document Object Model have different editors. A list of current W3C Recommendations and other technical documents can be found at http://www.w3.org/TR. Table of contents * Expanded Table of Contents * Copyright Notice * What is the Document Object Model? * Chapter 1: Document Object Model Core * Chapter 2: Document Object Model HTML * Chapter 3: Document Object Model Views * Chapter 4: Document Object Model StyleSheets * Chapter 5: Document Object Model CSS * Chapter 6: Document Object Model Events * Chapter 7: Document Object Model Traversal * Chapter 8: Document Object Model Range * Appendix A: Changes * Appendix B: Accessing code point boundaries * Appendix C: IDL Definitions * Appendix D: Java Language Binding * Appendix E: ECMA Script Language Binding * Acknowledgments * Glossary * References * Objects Index * Index Expanded Table of Contents * Expanded Table of Contents * Copyright Notice o W3C Document Copyright Notice and License o W3C Software Copyright Notice and License * What is the Document Object Model? o Introduction o What the Document Object Model is o What the Document Object Model is not o Where the Document Object Model came from o Entities and the DOM Core o Compliance o DOM Interfaces and DOM Implementations * Chapter 1: Document Object Model Core o 1.1. Overview of the DOM Core Interfaces + 1.1.1. The DOM Structure Model + 1.1.2. Memory Management + 1.1.3. Naming Conventions + 1.1.4. Inheritance vs Flattened Views of the API + 1.1.5. The DOMString type + 1.1.6. String comparisons in the DOM + 1.1.7. XML Namespaces o 1.2. Fundamental Interfaces o 1.3. Extended Interfaces * Chapter 2: Document Object Model HTML o 2.1. Introduction o 2.2. HTML Application of Core DOM + 2.2.1. Naming Conventions o 2.3. Miscellaneous Object Definitions o 2.4. Objects related to HTML documents o 2.5. HTML Elements + 2.5.1. Property Attributes + 2.5.2. Naming Exceptions + 2.5.3. Exposing Element Type Names ( tagName ) + 2.5.4. The HTMLElement interface + 2.5.5. Object definitions * Chapter 3: Document Object Model Views o 3.1. Introduction o 3.2. Interfaces * Chapter 4: Document Object Model StyleSheets o 4.1. Introduction o 4.2. Style Sheet Interfaces o 4.3. Document Extensions o 4.4. Association between a style sheet and a document. * Chapter 5: Document Object Model CSS o 5.1. Overview of the DOM Level 2 CSS Interfaces o 5.2. CSS Fundamental Interfaces + 5.2.1. Override and computed style sheet + 5.2.2. Style sheet creation + 5.2.3. Element with CSS inline style o 5.3. CSS Extended Interfaces * Chapter 6: Document Object Model Events o 6.1. Overview of the DOM Level 2 Event Model + 6.1.1. Terminology o 6.2. Description of event flow + 6.2.1. Basic event flow + 6.2.2. Event capture + 6.2.3. Event bubbling + 6.2.4. Event cancelation o 6.3. Event listener registration + 6.3.1. Event registration interfaces + 6.3.2. Interaction with HTML 4.0 event listeners o 6.4. Event interface o 6.5. DocumentEvent interface o 6.6. Event set definitions + 6.6.1. User Interface event types + 6.6.2. Mouse event types + 6.6.3. Key events + 6.6.4. Mutation event types + 6.6.5. HTML event types * Chapter 7: Document Object Model Traversal o 7.1. Overview + 7.1.1. Iterators + 7.1.2. Filters + 7.1.3. TreeWalker o 7.2. Formal Interface Definition * Chapter 8: Document Object Model Range o 8.1. Introduction o 8.2. Definitions and Notation + 8.2.1. Position + 8.2.2. Selection and Partial Selection + 8.2.3. Notation o 8.3. Creating a Range o 8.4. Changing a Range's Position o 8.5. Comparing Range Boundary-Points o 8.6. Deleting Content with a Range o 8.7. Extracting Content o 8.8. Cloning Content o 8.9. Inserting Content o 8.10. Surrounding Content o 8.11. Miscellaneous Members o 8.12. Range modification under document mutation + 8.12.1. Insertions + 8.12.2. Deletions o 8.13. Formal Description of the Range Interface * Appendix A: Changes o A.1. Changes between DOM Level 1 and DOM Level 2 + A.1.1. Changes to DOM Level 1 interfaces and exceptions + A.1.2. New interfaces * Appendix B: Accessing code point boundaries o B.1. Introduction o B.2. Methods * Appendix C: IDL Definitions o C.1. Document Object Model Core o C.2. Document Object Model HTML o C.3. Document Object Model Views o C.4. Document Object Model Stylesheets o C.5. Document Object Model CSS o C.6. Document Object Model Events o C.7. Document Object Model Traversal o C.8. Document Object Model Range * Appendix D: Java Language Binding o D.1. Document Object Model Core o D.2. Document Object Model HTML o D.3. Document Object Model Views o D.4. Document Object Model Stylesheets o D.5. Document Object Model CSS o D.6. Document Object Model Events o D.7. Document Object Model Traversal o D.8. Document Object Model Range * Appendix E: ECMA Script Language Binding o E.1. Document Object Model Core o E.2. Document Object Model HTML o E.3. Document Object Model Views o E.4. Document Object Model Stylesheets o E.5. Document Object Model CSS o E.6. Document Object Model Events o E.7. Document Object Model Traversal o E.8. Document Object Model Range * Acknowledgments * Glossary * References * Objects Index * Index Copyright Notice This document is published under the W3C Document Copyright Notice and License. The bindings within this document are published under the W3C Software Copyright Notice and License. The software license requires "Notice of any changes or modifications to the W3C files, including the date changes were made." Consequently, modified versions of the DOM bindings must document that they do not conform to the W3C standard; in the case of the IDL binding, the pragma prefix can no longer be 'w3c.org'; in the case of the Java binding, the package names can no longer be in the 'org.w3c' package. W3C Document Copyright Notice and License Copyright © 1995-1999 World Wide Web Consortium, (Massachusetts Institute of Technology, Institut National de Recherche en Informatique et en Automatique, Keio University). 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The full text of this NOTICE in a location viewable to users of the redistributed or derivative work. 2. Any pre-existing intellectual property disclaimers. If none exist, then a notice of the following form: "Copyright © World Wide Web Consortium, (Massachusetts Institute of Technology, Institut National de Recherche en Informatique et en Automatique, Keio University). All Rights Reserved. http://www.w3.org/Consortium/Legal/." 3. Notice of any changes or modifications to the W3C files, including the date changes were made. (We recommend you provide URIs to the location from which the code is derived). THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS. COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENTATION. The name and trademarks of copyright holders may NOT be used in advertising or publicity pertaining to the software without specific, written prior permission. Title to copyright in this software and any associated documentation will at all times remain with copyright holders. What is the Document Object Model? Editors Jonathan Robie, Software AG Introduction The Document Object Model (DOM) is an application programming interface (API) for HTML and XML documents. It defines the logical structure of documents and the way a document is accessed and manipulated. In the DOM specification, the term "document" is used in the broad sense - increasingly, XML is being used as a way of representing many different kinds of information that may be stored in diverse systems, and much of this would traditionally be seen as data rather than as documents. Nevertheless, XML presents this data as documents, and the DOM may be used to manage this data. With the Document Object Model, programmers can build documents, navigate their structure, and add, modify, or delete elements and content. Anything found in an HTML or XML document can be accessed, changed, deleted, or added using the Document Object Model, with a few exceptions - in particular, the DOM interfaces for the XML internal and external subsets have not yet been specified. As a W3C specification, one important objective for the Document Object Model is to provide a standard programming interface that can be used in a wide variety of environments and applications. The DOM is designed to be used with any programming language. In order to provide a precise, language-independent specification of the DOM interfaces, we have chosen to define the specifications in OMG IDL, as defined in the CORBA 2.2 specification [CORBA]. In addition to the OMG IDL specification, we provide language bindings for Java and ECMAScript (an industry-standard scripting language based on JavaScript and JScript) [Java] [ECMAScript]. Note: OMG IDL is used only as a language-independent and implementation-neutral way to specify interfaces. Various other IDLs could have been used. In general, IDLs are designed for specific computing environments. The Document Object Model can be implemented in any computing environment, and does not require the object binding runtimes generally associated with such IDLs. What the Document Object Model is The DOM is a programming API for documents. It is based on an object structure that closely resembles the structure of the documents it models. For instance, consider this table, taken from an HTML document:
Shady Grove Aeolian
Over the River, Charlie Dorian
The DOM represents this table like this: --------------------------------------------------------------------- [DOM representation of the example table] --------------------------------------------------------------------- DOM representation of the example table --------------------------------------------------------------------- In the DOM, documents have a logical structure which is very much like a tree; to be more precise, it is like a "forest" or "grove", which can contain more than one tree. Each document contains zero or one doctype nodes, one root element node, and zero or more comments or processing instructions; the root element serves as the root of the element tree for the document. However, the DOM does not specify that documents must be implemented as a tree or a grove, nor does it specify how the relationships among objects be implemented. The DOM is a logical model that may be implemented in any convenient manner. In this specification, we use the term structure model to describe the tree-like representation of a document. We also use the term "tree" when referring to the arrangement of those information items which can be reached by using "tree-walking" methods (this does not include attributes). This should not be taken as meaning that the DOM must be implemented as a tree structure. One important property of DOM structure models is structural isomorphism: if any two Document Object Model implementations are used to create a representation of the same document, they will create the same structure model, in accordance with the XML Information Set [Infoset]. The name "Document Object Model" was chosen because it is an "object model" in the traditional object oriented design sense: documents are modeled using objects, and the model encompasses not only the structure of a document, but also the behavior of a document and the objects of which it is composed. In other words, the nodes in the above diagram do not represent a data structure, they represent objects, which have functions and identity. As an object model, the DOM identifies: * the interfaces and objects used to represent and manipulate a document * the semantics of these interfaces and objects - including both behavior and attributes * the relationships and collaborations among these interfaces and objects The structure of SGML documents has traditionally been represented by an abstract data model, not by an object model. In an abstract data model, the model is centered around the data. In object oriented programming languages, the data itself is encapsulated in objects that hide the data, protecting it from direct external manipulation. The functions associated with these objects determine how the objects may be manipulated, and they are part of the object model. What the Document Object Model is not This section is designed to give a more precise understanding of the DOM by distinguishing it from other systems that may seem to be like it. * The Document Object Model is not a binary specification. DOM programs written in the same language will be source code compatible across platforms, but the DOM does not define any form of binary interoperability. * The Document Object Model is not a way of persisting objects to XML or HTML. Instead of specifying how objects may be represented in XML, the DOM specifies how XML and HTML documents are represented as objects, so that they may be used in object oriented programs. * The Document Object Model is not a set of data structures, it is an object model that specifies interfaces. Although this document contains diagrams showing parent/child relationships, these are logical relationships defined by the programming interfaces, not representations of any particular internal data structures. * The Document Object Model does not define what information in a document is relevant or how information in a document is structured. For XML, this is specified by the W3C XML Information Set [Infoset]. The DOM is simply an API to this information set. * The Document Object Model, despite its name, is not a competitor to the Component Object Model (COM). COM, like CORBA, is a language independent way to specify interfaces and objects; the DOM is a set of interfaces and objects designed for managing HTML and XML documents. The DOM may be implemented using language-independent systems like COM or CORBA; it may also be implemented using language-specific bindings like the Java or ECMAScript bindings specified in this document. Where the Document Object Model came from The DOM originated as a specification to allow JavaScript scripts and Java programs to be portable among Web browsers. "Dynamic HTML" was the immediate ancestor of the Document Object Model, and it was originally thought of largely in terms of browsers. However, when the DOM Working Group was formed at W3C, it was also joined by vendors in other domains, including HTML or XML editors and document repositories. Several of these vendors had worked with SGML before XML was developed; as a result, the DOM has been influenced by SGML Groves and the HyTime standard. Some of these vendors had also developed their own object models for documents in order to provide an API for SGML/XML editors or document repositories, and these object models have also influenced the DOM. Entities and the DOM Core In the fundamental DOM interfaces, there are no objects representing entities. Numeric character references, and references to the pre-defined entities in HTML and XML, are replaced by the single character that makes up the entity's replacement. For example, in:

This is a dog & a cat

the "&" will be replaced by the character "&", and the text in the P element will form a single continuous sequence of characters. Since numeric character references and pre-defined entities are not recognized as such in CDATA sections, or the SCRIPT and STYLE elements in HTML, they are not replaced by the single character they appear to refer to. If the example above were enclosed in a CDATA section, the "&" would not be replaced by "&"; neither would the

be recognized as a start tag. The representation of general entities, both internal and external, are defined within the extended (XML) interfaces of the Level 1 specification. Note: When a DOM representation of a document is serialized as XML or HTML text, applications will need to check each character in text data to see if it needs to be escaped using a numeric or pre-defined entity. Failing to do so could result in invalid HTML or XML. Also, implementations should be aware of the fact that serialization into a character encoding ("charset") that does not fully cover ISO 10646 may fail if there are characters in markup or CDATA sections that are not present in the encoding. Compliance The Document Object Model level 2 consists of several modules: Core, HTML, Views, StyleSheets, CSS, Events, Traversal, and Range. The DOM Core represents the functionality used for XML documents, and also serves as the basis for DOM HTML. A compliant implementation of the DOM must implement all of the fundamental interfaces in the Core chapter with the semantics as defined. Further, it must implement at least one of the HTML DOM and the extended (XML) interfaces with the semantics as defined. The other modules are optional. A DOM application can use the hasFeature method of the DOMImplementation interface to determine whether the module is supported or not. The feature strings for all modules in DOM Level 2 are listed in the following table (strings are case-insensitive): Module Feature String XML XML HTML HTML Views Views StyleSheets StyleSheets CSS CSS CSS (extended interfaces) CSS2 Events Events User Interface Events (UIEvent interface)UIEvents Mouse Events (MouseEvents interface) MouseEvents Mutation Events (MutationEvent interface)MutationEvents HTML Events HTMLEvents Traversal Traversal Range Range The following table contains all dependencies between modules: Module Implies Views XML or HTML StyleSheets StyleSheets and XML or HTML CSS StyleSheets, Views and XML or HTML CSS2 CSS, StyleSheets, Views and XML or HTML Events XML or HTML UIEvents Views, Events and XML or HTML MouseEvents UIEvents, Views, Events and XML or HTML MutationEventsEvents and XML or HTML HTMLEvents Events and XML or HTML DOM Interfaces and DOM Implementations The DOM specifies interfaces which may be used to manage XML or HTML documents. It is important to realize that these interfaces are an abstraction - much like "abstract base classes" in C++, they are a means of specifying a way to access and manipulate an application's internal representation of a document. Interfaces do not imply a particular concrete implementation. Each DOM application is free to maintain documents in any convenient representation, as long as the interfaces shown in this specification are supported. Some DOM implementations will be existing programs that use the DOM interfaces to access software written long before the DOM specification existed. Therefore, the DOM is designed to avoid implementation dependencies; in particular, 1. Attributes defined in the IDL do not imply concrete objects which must have specific data members - in the language bindings, they are translated to a pair of get()/set() functions, not to a data member. Read-only attributes have only a get() function in the language bindings. 2. DOM applications may provide additional interfaces and objects not found in this specification and still be considered DOM compliant. 3. Because we specify interfaces and not the actual objects that are to be created, the DOM can not know what constructors to call for an implementation. In general, DOM users call the createX() methods on the Document class to create document structures, and DOM implementations create their own internal representations of these structures in their implementations of the createX() functions. The Level 1 interfaces were extended to provide both Level 1 and Level 2 functionality. DOM implementations in languages other than Java or ECMA Script may choose bindings that are appropriate and natural for their language and run time environment. For example, some systems may need to create a Document2 class which inherits from Document and contains the new methods and attributes. 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) 1.1. Overview of the DOM Core Interfaces This section defines a 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: * Document -- Element (maximum of one), ProcessingInstruction, Comment, DocumentType (maximum of one) * DocumentFragment -- Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference * DocumentType -- no children * EntityReference -- Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference * Element -- Element, Text, Comment, ProcessingInstruction, CDATASection, EntityReference * Attr -- Text, EntityReference * ProcessingInstruction -- no children * Comment -- no children * Text -- no children * CDATASection -- no children * Entity -- Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference * Notation -- no children 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, some 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 DOMString; * Applications must encode DOMString using UTF-16 (defined in [Unicode] and Amendment 1 of [ISO/IEC 10646]). The UTF-16 encoding was chosen because of its widespread industry practice. 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 negotiation to decide the width and encoding of a character. 1.1.6. String comparisons 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. In addition, the DOM assumes that any normalizations take place in the processor, before the DOM structures are built. Note: 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. However, nodes are permanently bound to namespace URIs as they get created. Consequently, 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. Namespace validation is not enforced; the DOM application is responsible. In particular, since the mapping between prefixes and namespace URIs is not enforced, in general, the resulting document cannot be serialized naively. For example, applications may have to declare every namespace in use when serializing a document. In a document with no namespaces, the child list of an EntityReference node is always the same as that of the corresponding Entity. This is not true in a document where an entity contains unbound namespace prefixes. In such a case, the descendants of the corresponding EntityReference nodes may be bound to different namespace URIs, depending on where the entity references are. Also, because in the DOM nodes always remain bound to the same namespace URI, moving such EntityReference nodes can lead to documents that cannot be serialized. This is also true when the DOM Level 1 method createEntityReference of the Document interface is used to create entity references that correspond to such entities, since the descendants of the returned EntityReference are unbound. The DOM Level 2 does not support any mechanism to resolve namespace prefixes. For all of these reasons, use of such entities and entity references should be avoided or used with extreme care. A future level of the DOM may include some additional support for handling these. 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, namespace URI, and local name. Note: While it is safe to use these DOM Level 1 methods when not dealing with namespaces, using them and the new ones at the same time should be avoided. DOM Level 1 methods, which are namespaces ignorant, solely identify attribute nodes by their nodeName. On the contrary, the DOM Level 2 methods related to namespaces, identify attribute nodes by their namespaceURI and localName. Because of this fundamental difference, mixing both sets of methods can lead to unpredictable results. In particular, using setAttributeNS, one can set on an element two attributes (or more) that have the same nodeName, but different namespaceURIs. Calling getAttribute with that nodeName could then return any of those attributes. The result is implementation dependent. Similarly, using setAttributeNode, one can set two attributes (or more) that have different nodeNames but the same prefix and namespaceURI. In this case getAttributeNodeNS will return one or the other, in a platform dependent manner. The only guarantee in such cases, is that setAttribute and setAttributeNS affect the node that, respectively, getAttribute and getAttributeNS return. 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; // Introduced in DOM Level 2: const unsigned short INVALID_STATE_ERR = 11; // Introduced in DOM Level 2: const unsigned short SYNTAX_ERR = 12; // Introduced in DOM Level 2: const unsigned short INVALID_MODIFICATION_ERR = 13; // Introduced in DOM Level 2: const unsigned short NAMESPACE_ERR = 14; // Introduced in DOM Level 2: const unsigned short INVALID_ACCESS_ERR = 15; Definition group ExceptionCode An integer indicating the type of error generated. Note: Other numeric codes are reserved to W3C for possible future use. 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 If a node is used in a different WRONG_DOCUMENT_ERR document than the one that created it (that doesn't support it) If an invalid or illegal character is specified, such as in a name. See production 2 in INVALID_CHARACTER_ERR the XML specification for the definition of a legal character, and production 5 for the definition of a legal name character. NO_DATA_ALLOWED_ERR If data is specified for a node which does not support data If an attempt is made to modify NO_MODIFICATION_ALLOWED_ERR an object where modifications are not allowed If an attempt is made to NOT_FOUND_ERR reference a node in a context where it does not exist If the implementation does not NOT_SUPPORTED_ERR support the type of object requested If an attempt is made to add an INUSE_ATTRIBUTE_ERR attribute that is already inuse elsewhere Introduced in DOM Level 2. INVALID_STATE_ERR If an attempt is made to use an object that is not, or no longer, usable. Introduced in DOM Level 2. SYNTAX_ERR If an invalid or illegal string is specified. Introduced in DOM Level 2. INVALID_MODIFICATION_ERR If an attempt is made to modify the type of the underlying object. Introduced in DOM Level 2. If an attempt is made to create NAMESPACE_ERR or change an object in a way which is incorrect with regard to namespaces. Introduced in DOM Level 2. INVALID_ACCESS_ERR If a parameter or an operation is not supported by the underlying object. 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, in DOMString internalSubset); // 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 string of the feature to test (case-insensitive). The legal values are defined throughout this specification. The string must be an XML name (see also Compliance). DOMString version This is the version number of the feature 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. Entity declarations and notations are not made available. Entity reference expansions and default attribute additions do not occur. It is expected that a future version of the DOM will provide a way for populating a DocumentType. 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 external subset public identifier. DOMString systemId The external subset system identifier. DOMString internalSubset The internal subset as a string. This should be valid. 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); // Introduced in DOM Level 2: Element getElementById(in DOMString elementId); }; 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 with the nodeName attribute set to tagName, and localName, prefix, and namespaceURI set to null. Exceptions DOMException INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character. createDocumentFragment Creates an empty DocumentFragment object. Return Value DocumentFragment A new DocumentFragment. 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 ProcessingInstruction The new ProcessingInstruction object. Exceptions DOMException INVALID_CHARACTER_ERR: Raised if an illegal 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 with the nodeName attribute set to name, and localName, prefix, and namespaceURI set to null. Exceptions DOMException INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character. createEntityReference Creates an EntityReference object. In addition, if the referenced entity is known, the child list of the EntityReference node is made the same as that of the corresponding Entity node. Note: If any descendant of the Entity node has an unbound namespace prefix, the corresponding descendant of the created EntityReference node is also unbound (its namespaceURI is null). The DOM Level 2 does not support any mechanism to resolve namespace prefixes. Parameters DOMString name The name of the entity to reference. Return Value EntityReference The new EntityReference object. Exceptions DOMException INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal 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 can be imported, however in the current release of the DOM the DocumentType is readonly. Ability to add these imported nodes to a DocumentType will be considered for addition to a future release of the DOM. On import, the publicId, and systemId attributes are copied. Note that the deep parameter 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. If the given namespaceURI is null or an empty string and the qualifiedName has a prefix that is "xml", the created element is bound to the predefined namespace "http://www.w3.org/XML/1998/namespace" [Namespaces]. HTML-only DOM implementations do not need to implement this method. Parameters DOMString namespaceURI The namespace URI of the element to create. DOMString qualifiedName The qualified name of the element type to instantiate. Return Value Element A new Element object with the following attributes: Attribute Value Node.nodeName qualifiedName Node.namespaceURInamespaceURI, or "http://www.w3.org/XML/1998/namespace" if namespaceURI is null or an empty string, and the prefix is "xml" Node.prefix prefix, extracted from qualifiedName, or null if there is no prefix Node.localName local name, extracted from qualifiedName Element.tagName qualifiedName Exceptions DOMException INVALID_CHARACTER_ERR: Raised if the specified qualified name contains an illegal character. NAMESPACE_ERR: Raised if the qualifiedName is malformed, or if the qualifiedName has a prefix that is "xml" and the namespaceURI is neither null nor an empty string nor "http://www.w3.org/XML/1998/namespace". createAttributeNS introduced in DOM Level 2 Creates an attribute of the given qualified name and namespace URI. If the given namespaceURI is null or an empty string and the qualifiedName has a prefix that is "xml", the created attribute is bound to the predefined namespace "http://www.w3.org/XML/1998/namespace" [Namespaces]. HTML-only DOM implementations do not need to implement this method. Parameters DOMString namespaceURI The namespace URI of the attribute to create. DOMString qualifiedName The qualified name of the attribute to instantiate. Return Value Attr A new Attr object with the following attributes: Attribute Value Node.nodeName qualifiedName Node.namespaceURInamespaceURI, or "http://www.w3.org/XML/1998/namespace" if namespaceURI is null or an empty string and the prefix is "xml" Node.prefix prefix, extracted from qualifiedName, or null if there is no prefix Node.localName local name, extracted from qualifiedName Attr.name qualifiedName Exceptions DOMException INVALID_CHARACTER_ERR: Raised if the specified qualified name contains an illegal character. NAMESPACE_ERR: Raised if the qualifiedName is malformed, if the qualifiedName has a prefix that is "xml" and the namespaceURI is neither null nor an empty string nor "http://www.w3.org/XML/1998/namespace", or if the qualifiedName has a prefix that is "xmlns" but the namespaceURI is neither null nor an empty string. 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. 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 getElementById introduced in DOM Level 2 Returns the Element whose ID is given by elementId. If no such element exists, returns null. Behavior is not defined if more than one element has this ID. Note: The DOM implementation must have information that says which attributes are of type ID. Attributes with the name "ID" are not of type ID unless so defined. Implementations that do not know whether attributes are of type ID or not are expected to return null. Parameters DOMString elementId The unique id value for an element. Return Value Element The matching element. 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: void normalize(); // 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. Note: Other numeric codes are reserved to W3C for possible future use. 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: nodeName nodeValue attributes Element tag name null NamedNodeMap Attr name of attribute value of null attribute Text #text content of null the text node CDATASection #cdata-section content of null the CDATA Section EntityReference name of entity null null referenced Entity entity name null null ProcessingInstructiontarget entire null content excluding the target Comment #comment content of null the comment Document #document null null DocumentType document type name null null DocumentFragment #document-fragment null null Notation notation name null null 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. 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 of any type other than ELEMENT_NODE and ATTRIBUTE_NODE and nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is always null. Note: Per the Namespaces in XML Specification [Namespaces] an attribute does not inherit its namespace from the element it is attached to. If an attribute is not explicitly given a namespace, it simply has no namespace. prefix of type DOMString, introduced in DOM Level 2 The namespace prefix of this node, or null if it is unspecified. Note that setting this attribute, when permitted, 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. Note also that changing the prefix of an attribute, that is known to have a default value, does not make a new attribute with the default value and the original prefix appear, since the namespaceURI and localName do not change. Exceptions on setting DOMException INVALID_CHARACTER_ERR: Raised if the specified prefix contains an illegal character. NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NAMESPACE_ERR: Raised if the specified prefix is malformed, if the specified prefix is "xml" and the namespaceURI of this node is different from "http://www.w3.org/XML/1998/namespace", if specified prefix is "xmlns" and the namespaceURI is neither null nor an empty string, or if the localName is null [Namespaces]. 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, it is null. 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 or the node being inserted 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 newChild is a DocumentFragment object, refChild is replaced by all of the DocumentFragment children, which are inserted in the same order. 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 or the new 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 or the node being appended 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. Note that cloning an immutable subtree results in a mutable copy, but the children of an EntityReference clone are readonly. 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 normalize introduced in DOM Level 2 Puts all Text nodes in the full depth of the sub-tree underneath this Node, including attribute nodes, 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. Note: In cases where the document contains CDATASections, the normalize operation alone may not be sufficient, since XPointers do not differentiate between Text nodes and CDATASection nodes. No Parameters No Return Value 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 string of the feature to test. This is the same name that which can be passed to the method hasFeature on DOMImplementation. DOMString version This is the version number of the feature 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 the specified feature is supported on this node, 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 setNamedItemNS(in Node arg) raises(DOMException); // Introduced in DOM Level 2: Node removeNamedItemNS(in DOMString namespaceURI, in DOMString localName) 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 The nodeName of a node to retrieve. Return Value Node A Node (of any type) with the specified nodeName, or null if it does not identify any node in the map. No Exceptions setNamedItem Adds a node using its nodeName attribute. 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 the replaced 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 nodeName 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 as well as the corresponding namespace URI, local name, and prefix when applicable. 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. NO_MODIFICATION_ALLOWED_ERR: Raised if this NamedNodeMap is readonly. 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. DOMString localName The local name of the node to retrieve. Return Value Node A Node (of any type) with the specified local name and namespace URI, or null if they do not identify any node in the map. No Exceptions setNamedItemNS introduced in DOM Level 2 Adds a node using its namespaceURI and localName. HTML-only DOM implementations do not need to implement this method. Parameters Node arg A node to store in a named node map. The node will later be accessible using the value of the namespaceURI and localName attribute of the node. If a node with those namespace URI and local 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 the replaced 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. 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. DOMString localName 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 as well as the corresponding namespace URI, local name, and prefix. 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. NO_MODIFICATION_ALLOWED_ERR: Raised if this NamedNodeMap is readonly. 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. As explained in the DOMString interface, text strings in the DOM are represented in UTF-16, i.e. as a sequence of 16-bit units. In the following, the term 16-bit units is used whenever necessary to indicate that indexing on CharacterData is done in 16-bit units. 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. See also the method getAttribute on the Element interface. On setting, this creates a Text node with the unparsed contents of the string. I.e. any characters that an XML processor would recognize as markup are instead treated as literal text. See also the method setAttribute on the Element interface. 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: 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. Note: In DOM Level 2, the method normalize is inherited from the Node interface where it was moved. 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); // 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 qualifiedName, in DOMString value) raises(DOMException); // Introduced in DOM Level 2: void removeAttributeNS(in DOMString namespaceURI, 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: ... , 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. To set an attribute with a qualified name and namespace URI, use the setAttributeNS method. 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 illegal 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 as well as the corresponding namespace URI, local name, and prefix when applicable. To remove an attribute by local name and namespace URI, use the removeAttributeNS method. 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 attribute node by name. To retrieve an attribute node by qualified name and namespace URI, use the getAttributeNodeNS method. Parameters DOMString name The name (nodeName) of the attribute to retrieve. Return Value Attr The Attr node with the specified name (nodeName) or null if there is no such attribute. No Exceptions setAttributeNode Adds a new attribute node. If an attribute with that name (nodeName) is already present in the element, it is replaced by the new one. To add a new attribute node with a qualified name and namespace URI, use the setAttributeNodeNS method. Parameters Attr