W3C

W3C DOM4

W3C Last Call Working Draft

This version:
http://www.w3.org/TR/2014/WD-dom-20140710/
Latest published version:
http://www.w3.org/TR/dom/
Latest editor's draft:
http://w3c.github.io/dom/
Bug tracker:
file a bug (open bugs)
Previous version:
http://www.w3.org/TR/2014/CR-dom-20140508/
Editors:
Anne van Kesteren, Mozilla (Upstream WHATWG version)
Aryeh Gregor, Mozilla (Upstream WHATWG version)
Ms2ger, Mozilla (Upstream WHATWG version)
Alex Russell, Google
Robin Berjon, W3C

Abstract

DOM defines a platform-neutral model for events and node trees.

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

This document is published as a snapshot of the DOM Living Standard with the intent of keeping the differences from the original to a strict minimum, and only through subsetting (only things that are not implemented were removed for this publication).

Since this document has already been through the Candidate Recommendation stage, the Working Group expects to advance it to Proposed Recommendation at the end of this Last Call period.

This document was published by the HTML Working Group as a Last Call Working Draft. This document is intended to become a W3C Recommendation. If you wish to make comments regarding this document, please send them to www-dom@w3.org (subscribe, archives). The Last Call period ends 31 July 2014. All comments are welcome.

Publication as a Last Call Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This is a Last Call Working Draft and thus the Working Group has determined that this document has satisfied the relevant technical requirements and is sufficiently stable to advance through the Technical Recommendation process.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

Table of Contents

  1. Goals
  2. 1 Conformance
    1. 1.1 Dependencies
    2. 1.2 Extensibility
  3. 2 Terminology
    1. 2.1 Trees
    2. 2.2 Strings
    3. 2.3 Ordered sets
    4. 2.4 Namespaces
  4. 3 Errors
    1. 3.1 Exception DOMException
    2. 3.2 Interface DOMError
    3. 3.3 Error names
  5. 4 Events
    1. 4.1 Introduction to "DOM Events"
    2. 4.2 Interface Event
    3. 4.3 Interface CustomEvent
    4. 4.4 Constructing events
    5. 4.5 Defining event interfaces
    6. 4.6 Interface EventTarget
    7. 4.7 Dispatching events
    8. 4.8 Firing events
  6. 5 Nodes
    1. 5.1 Introduction to "The DOM"
    2. 5.2 Node tree
      1. 5.2.1 Mutation algorithms
      2. 5.2.2 Interface NonElementParentNode
      3. 5.2.3 Interface ParentNode
      4. 5.2.4 Interface NonDocumentTypeChildNode
      5. 5.2.5 Interface ChildNode
      6. 5.2.6 Old-style collections: NodeList and HTMLCollection
        1. 5.2.6.1 Interface NodeList
        2. 5.2.6.2 Interface HTMLCollection
    3. 5.3 Mutation observers
      1. 5.3.1 Interface MutationObserver
      2. 5.3.2 Queuing a mutation record
      3. 5.3.3 Interface MutationRecord
      4. 5.3.4 Garbage collection
    4. 5.4 Interface Node
    5. 5.5 Interface Document
      1. 5.5.1 Interface DOMImplementation
    6. 5.6 Interface DocumentFragment
    7. 5.7 Interface DocumentType
    8. 5.8 Interface Element
      1. 5.8.1 Interface Attr
    9. 5.9 Interface CharacterData
    10. 5.10 Interface Text
    11. 5.11 Interface ProcessingInstruction
    12. 5.12 Interface Comment
  7. 6 Ranges
    1. 6.1 Introduction to "DOM Ranges"
    2. 6.2 Interface Range
  8. 7 Traversal
    1. 7.1 Interface NodeIterator
    2. 7.2 Interface TreeWalker
    3. 7.3 Interface NodeFilter
  9. 8 Sets
    1. 8.1 Interface DOMTokenList
    2. 8.2 Interface DOMSettableTokenList
  10. 9 Historical
    1. 9.1 DOM Events
    2. 9.2 DOM Core
    3. 9.3 DOM Ranges
    4. 9.4 DOM Traversal
  11. References
  12. Acknowledgments

Goals

This specification standardizes the DOM. It does so as follows:

  1. By consolidating DOM Level 3 Core [DOM3CORE], Element Traversal [ELEMENTTRAVERSAL], Selectors API Level 2 [SELECTORSAPI], the "DOM Event Architecture" and "Basic Event Interfaces" chapters of DOM Level 3 Events [DOM3EVENTS] (specific type of events do not belong in the base specification), and DOM Level 2 Traversal and Range [DOM2TR], and:

  2. By moving features from the HTML standard that ought to be part of the DOM platform here. [HTML]

  3. By defining a replacement for the "Mutation Events" and "Mutation Name Event Types" chapters of DOM Level 3 Events [DOM3EVENTS] as the old model was problematic.

    The old model is expected to be removed from implementations in due course.

  4. By defining new features that simplify common DOM operations.

1 Conformance

All diagrams, examples, and notes in this specification are non-normative, as are all sections explicitly marked non-normative. Everything else in this specification is normative.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. For readability, these words do not appear in all uppercase letters in this specification. [RFC2119]

Requirements phrased in the imperative as part of algorithms (such as "strip any leading space characters" or "return false and terminate these steps") are to be interpreted with the meaning of the key word ("must", "should", "may", etc) used in introducing the algorithm.

Conformance requirements phrased as algorithms or specific steps may be implemented in any manner, so long as the end result is equivalent. (In particular, the algorithms defined in this specification are intended to be easy to follow, and not intended to be performant.)

User agents may impose implementation-specific limits on otherwise unconstrained inputs, e.g. to prevent denial of service attacks, to guard against running out of memory, or to work around platform-specific limitations.

When a method or an attribute is said to call another method or attribute, the user agent must invoke its internal API for that attribute or method so that e.g. the author can't change the behavior by overriding attributes or methods with custom properties or functions in JavaScript.

Unless otherwise stated, string comparisons are done in a case-sensitive manner.

1.1 Dependencies

The IDL fragments in this specification must be interpreted as required for conforming IDL fragments, as described in the Web IDL specification. [WEBIDL]

Some of the terms used in this specification are defined in Encoding, Selectors, Web IDL, XML, and Namespaces in XML. [ENCODING] [SELECTORS] [WEBIDL] [XML] [XMLNS]

1.2 Extensibility

Vendor-specific proprietary extensions to this specification are strongly discouraged. Authors must not use such extensions, as doing so reduces interoperability and fragments the user base, allowing only users of specific user agents to access the content in question.

If vendor-specific extensions are needed, the members should be prefixed by vendor-specific strings to prevent clashes with future versions of this specification. Extensions must be defined so that the use of extensions neither contradicts nor causes the non-conformance of functionality defined in the specification.

When vendor-neutral extensions to this specification are needed, either this specification can be updated accordingly, or an extension specification can be written that overrides the requirements in this specification. When someone applying this specification to their activities decides that they will recognize the requirements of such an extension specification, it becomes an applicable specification for the purposes of conformance requirements in this specification.

2 Terminology

The term context object means the object on which the algorithm, attribute getter, attribute setter, or method being discussed was called. When the context object is unambiguous, the term can be omitted.

2.1 Trees

A tree is a finite hierarchical tree structure. In tree order is preorder, depth-first traversal of a tree.

An object that participates in a tree has a parent, which is either another object or null, and an ordered list of zero or more child objects. An object A whose parent is object B is a child of B.

The root of an object is itself, if its parent is null, or else it is the root of its parent.

An object A is called a descendant of an object B, if either A is a child of B or A is a child of an object C that is a descendant of B.

An inclusive descendant is an object or one of its descendants.

An object A is called an ancestor of an object B if and only if B is a descendant of A.

An inclusive ancestor is an object or one of its ancestors.

An object A is called a sibling of an object B, if and only if B and A share the same non-null parent.

An object A is preceding an object B if A and B are in the same tree and A comes before B in tree order.

An object A is following an object B if A and B are in the same tree and A comes after B in tree order.

The first child of an object is its first child or null if it has no child.

The last child of an object is its last child or null if it has no child.

The previous sibling of an object is its first preceding sibling or null if it has no preceding sibling.

The next sibling of an object is its first following sibling or null if it has no following sibling.

The index of an object is its number of preceding siblings.

2.2 Strings

Comparing two strings in a case-sensitive manner means comparing them exactly, code point for code point.

Comparing two strings in a ASCII case-insensitive manner means comparing them exactly, code point for code point, except that the characters in the range U+0041 .. U+005A (i.e. LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and the corresponding characters in the range U+0061 .. U+007A (i.e. LATIN SMALL LETTER A to LATIN SMALL LETTER Z) are considered to also match.

Converting a string to ASCII uppercase means replacing all characters in the range U+0061 to U+007A (i.e. LATIN SMALL LETTER A to LATIN SMALL LETTER Z) with the corresponding characters in the range U+0041 to U+005A (i.e. LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z).

Converting a string to ASCII lowercase means replacing all characters in the range U+0041 to U+005A (i.e. LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) with the corresponding characters in the range U+0061 to U+007A (i.e. LATIN SMALL LETTER A to LATIN SMALL LETTER Z).

A string pattern is a prefix match for a string s when pattern is not longer than s and truncating s to pattern's length leaves the two strings as matches of each other.

2.3 Ordered sets

The ordered set parser takes a string input and then runs these steps:

  1. Let position be a pointer into input, initially pointing at the start of the string.

  2. Let tokens be an ordered set of tokens, initially empty.

  3. Skip ASCII whitespace.

  4. While position is not past the end of input:

    1. Collect a code point sequence of code points that are not ASCII whitespace.

    2. If the collected string is not in tokens, append the collected string to tokens.

    3. Skip ASCII whitespace.

  5. Return tokens.

To collect a code point sequence of code points, run these steps:

  1. Let input and position be the same variables as those of the same name in the algorithm that invoked these steps.

  2. Let result be the empty string.

  3. While position does not point past the end of input and the code point at position is one of code points, append that code point to the end of result and advance position to the next code point in input.

  4. Return result.

To skip ASCII whitespace means to collect a code point sequence of ASCII whitespace and discard the return value.

The ordered set serializer takes a set and returns the concatenation of the strings in set, separated from each other by U+0020.

2.4 Namespaces

The HTML namespace is http://www.w3.org/1999/xhtml.

The XML namespace is http://www.w3.org/XML/1998/namespace.

The XMLNS namespace is http://www.w3.org/2000/xmlns/.

3 Errors

This entire section will move out of DOM into IDL. Use this standard as reference for DOMException until that has happened. Replace instances of DOMError with DOMException as DOMError will be nuked from orbit soon.

3.1 Exception DOMException

exception DOMException {
  const unsigned short INDEX_SIZE_ERR = 1;
  const unsigned short DOMSTRING_SIZE_ERR = 2; // historical
  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; // historical
  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; // historical
  const unsigned short INVALID_STATE_ERR = 11;
  const unsigned short SYNTAX_ERR = 12;
  const unsigned short INVALID_MODIFICATION_ERR = 13;
  const unsigned short NAMESPACE_ERR = 14;
  const unsigned short INVALID_ACCESS_ERR = 15;
  const unsigned short VALIDATION_ERR = 16; // historical
  const unsigned short TYPE_MISMATCH_ERR = 17; // historical; use JavaScript's TypeError instead
  const unsigned short SECURITY_ERR = 18;
  const unsigned short NETWORK_ERR = 19;
  const unsigned short ABORT_ERR = 20;
  const unsigned short URL_MISMATCH_ERR = 21;
  const unsigned short QUOTA_EXCEEDED_ERR = 22;
  const unsigned short TIMEOUT_ERR = 23;
  const unsigned short INVALID_NODE_TYPE_ERR = 24;
  const unsigned short DATA_CLONE_ERR = 25;
  unsigned short code;
};

The code exception field must return the value it was initialized to.

To throw a name exception run these steps:

  1. Let code be zero.

  2. If name is in the first column of the error names table and has a corresponding legacy code exception field value in the third column, set code to that value.

  3. Throw a new DOMException exception, whose message is a user agent-defined value, name is name, and whose code exception field is code.

To throw a "TimeoutError" exception, a user agent would construct a DOMException exception whose name is "TimeoutError" and code exception field value is 23, and actually throw that object as an exception. In JavaScript, this exception will have a name property whose value is "TimeoutError".

3.2 Interface DOMError

[Constructor(DOMString name, optional DOMString message = "")]
interface DOMError {
  readonly attribute DOMString name;
  readonly attribute DOMString message;
};

DOMError will be nuked. Replace your usage with DOMException now.

The DOMError(name, message) constructor must return a new DOMError object whose name attribute is initialized to name and whose message attribute is initialized to message.

The name attribute must return the value it was initialized to.

The message attribute must return the value it was initialized to.

The value of the message will typically be implementation-dependent and for informational purposes only.

A name DOMError means a DOMError object whose name attribute is initialized to name and whose message attribute is initialized to a helpful implementation-dependent message that explains the error.

A specification could say that an error attribute must return a "SyntaxError" DOMError.

3.3 Error names

The error names table below lists all the allowed error names, a description, and legacy code exception field values (when the error name is used for throwing an exception).

If an error name is not listed here, please file a bug as indicated at the top of this specification and it will be addressed shortly. Thanks!

NameDescriptionLegacy code exception field value (if any)
"IndexSizeError" The index is not in the allowed range. INDEX_SIZE_ERR (1)
"HierarchyRequestError" The operation would yield an incorrect node tree. HIERARCHY_REQUEST_ERR (3)
"WrongDocumentError" The object is in the wrong document. WRONG_DOCUMENT_ERR (4)
"InvalidCharacterError" The string contains invalid characters. INVALID_CHARACTER_ERR (5)
"NoModificationAllowedError" The object can not be modified. NO_MODIFICATION_ALLOWED_ERR (7)
"NotFoundError" The object can not be found here. NOT_FOUND_ERR (8)
"NotSupportedError" The operation is not supported. NOT_SUPPORTED_ERR (9)
"InvalidStateError" The object is in an invalid state. INVALID_STATE_ERR (11)
"SyntaxError" The string did not match the expected pattern. SYNTAX_ERR (12)
"InvalidModificationError" The object can not be modified in this way. INVALID_MODIFICATION_ERR (13)
"NamespaceError" The operation is not allowed by Namespaces in XML. [XMLNS] NAMESPACE_ERR (14)
"InvalidAccessError" The object does not support the operation or argument. INVALID_ACCESS_ERR (15)
"SecurityError" The operation is insecure. SECURITY_ERR (18)
"NetworkError" A network error occurred. NETWORK_ERR (19)
"AbortError" The operation was aborted. ABORT_ERR (20)
"URLMismatchError" The given URL does not match another URL. URL_MISMATCH_ERR (21)
"QuotaExceededError" The quota has been exceeded. QUOTA_EXCEEDED_ERR (22)
"TimeoutError" The operation timed out. TIMEOUT_ERR (23)
"InvalidNodeTypeError" The supplied node is incorrect or has an incorrect ancestor for this operation. INVALID_NODE_TYPE_ERR (24)
"DataCloneError" The object can not be cloned. DATA_CLONE_ERR (25)
"EncodingError" The encoding operation (either encoded or decoding) failed.
"NotReadableError" The I/O read operation failed.

4 Events

4.1 Introduction to "DOM Events"

Throughout the web platform events are dispatched to objects to signal an occurrence, such as network activity or user interaction. These objects implement the EventTarget interface and can therefore add event listeners to observe events:

obj.addEventListener("load", imgFetched)

function imgFetched(ev) {
  // great success
  …
}

Event listeners can be removed by utilizing the removeEventListener() method, passing the same arguments.

Events are objects too and implement the Event interface (or a derived interface). In the example above ev is the event. It is passed as argument to event listener's callback (typically a JavaScript Function as shown above). Event listeners key off the event's type attribute value ("load" in the above example). The event's target attribute value returns the object to which the event was dispatched (obj above).

Now while typically events are dispatched by the user agent as the result of user interaction or the completion of some task, applications can dispatch events themselves, commonly known as synthetic events:

// add an appropriate event listener
obj.addEventListener("cat", function(e) { process(e.detail) })

// create and dispatch the event
var event = new CustomEvent("cat", {"detail":{"hazcheeseburger":true}})
obj.dispatchEvent(event)

Apart from signaling, events are sometimes also used to let an application control what happens next in an operation. For instance as part of form submission an event whose type attribute value is "submit" is dispatched. If this event's preventDefault() method is invoked, form submission will be terminated. Applications who wish to make use of this functionality through events dispatched by the application (synthetic events) can make use of the return value of the dispatchEvent() method:

if(obj.dispatchEvent(event)) {
  // event was not canceled, time for some magic
  …
}

When an event is dispatched to an object that participates in a tree (e.g. an element), it can reach event listeners on that object's ancestors too. First all object's ancestor event listeners whose capture variable is set to true are invoked, in tree order. Second, object's own event listeners are invoked. And finally, and only if event's bubbles attribute value is true, object's ancestor event listeners are invoked again, but now in reverse tree order.

Lets look at an example on how events work in a tree:

<!doctype html>
<html>
 <head>
  <title>Boring example</title>
 </head>
 <body>
  <p>Hello <span id=x>world</span>!</p>
  <script>
   function test(e) {
     debug(e.target, e.currentTarget, e.eventPhase)
   }
   document.addEventListener("hey", test, true)
   document.body.addEventListener("hey", test)
   var ev = new Event("hey", {bubbles:true})
   document.getElementById("x").dispatchEvent(ev)
  </script>
 </body>
</html>

The debug function will be invoked twice. Each time the events's target attribute value will be the span element. The first time currentTarget attribute's value will be the document, the second time the body element. eventPhase attribute's value switches from CAPTURING_PHASE to BUBBLING_PHASE. If an event listener was registered for the span element, eventPhase attribute's value would have been AT_TARGET.

4.2 Interface Event

[Constructor(DOMString type, optional EventInit eventInitDict),
 Exposed=Window,Worker]
interface Event {
  readonly attribute DOMString type;
  readonly attribute EventTarget? target;
  readonly attribute EventTarget? currentTarget;

  const unsigned short NONE = 0;
  const unsigned short CAPTURING_PHASE = 1;
  const unsigned short AT_TARGET = 2;
  const unsigned short BUBBLING_PHASE = 3;
  readonly attribute unsigned short eventPhase;

  void stopPropagation();
  void stopImmediatePropagation();

  readonly attribute boolean bubbles;
  readonly attribute boolean cancelable;
  void preventDefault();
  readonly attribute boolean defaultPrevented;

  [Unforgeable] readonly attribute boolean isTrusted;
  readonly attribute DOMTimeStamp timeStamp;

  void initEvent(DOMString type, boolean bubbles, boolean cancelable);
};

dictionary EventInit {
  boolean bubbles = false;
  boolean cancelable = false;
};

An event allows for signaling that something has occurred. E.g. that an image has completed downloading. It is represented by the Event interface or an interface that inherits from the Event interface.

event = new Event(type [, eventInitDict])

Returns a new event whose type attribute value is set to type. The optional eventInitDict argument allows for setting the bubbles and cancelable attributes via object members of the same name.

event . type

Returns the type of event, e.g. "click", "hashchange", or "submit".

event . target

Returns the object event is dispatched to.

event . currentTarget

Returns the object whose event listener's callback is invoked.

event . eventPhase

Returns the event's phase, which is one of NONE, CAPTURING_PHASE, AT_TARGET, and BUBBLING_PHASE.

event . stopPropagation()

When dispatched in a tree, invoking this method prevents event from reaching any other objects than the current.

event . stopImmediatePropagation()

Invoking this method prevents event from reaching any event listeners registered after the current one and when dispatched in a tree also prevents event from reaching any other objects.

event . bubbles

Returns true if event's goes through its target attribute value's ancestors in reverse tree order, and false otherwise.

event . cancelable

Returns true or false depending on how event was initialized. Its return value does not always carry meaning, but true can indicate that part of the operation during which event was dispatched, can be canceled by invoking the preventDefault() method.

event . preventDefault()

If invoked when the cancelable attribute value is true, signals to the operation that caused event to be dispatched that it needs to be canceled.

event . defaultPrevented

Returns true if preventDefault() was invoked while the cancelable attribute value is true, and false otherwise.

event . isTrusted

Returns true if event was dispatched by the user agent, and false otherwise.

event . timeStamp

Returns the creation time of event in the number of milliseconds that passed since 00:00:00 UTC on 1 January 1970.

The type attribute must return the value it was initialized to. When an event is created the attribute must be initialized to the empty string.

The target and currentTarget attributes must return the values they were initialized to. When an event is created the attributes must be initialized to null.

The eventPhase attribute must return the value it was initialized to, which must be one of the following:

NONE (numeric value 0)

Events not currently dispatched are in this phase.

CAPTURING_PHASE (numeric value 1)

When an event is dispatched to an object that participates in a tree it will be in this phase before it reaches its target attribute value.

AT_TARGET (numeric value 2)

When an event is dispatched it will be in this phase on its target attribute value.

BUBBLING_PHASE (numeric value 3)

When an event is dispatched to an object that participates in a tree it will be in this phase after it reaches its target attribute value.

Initially the attribute must be initialized to NONE.


Each event has the following associated flags that are all initially unset:

The stopPropagation() method must set the stop propagation flag.

The stopImmediatePropagation() method must set both the stop propagation flag and stop immediate propagation flag.

The bubbles and cancelable attributes must return the values they were initialized to. When an event is created, they must be initialized to false. The EventInit dictionary is not sufficient due to the existence of the legacy createEvent().

The preventDefault() method must set the canceled flag if the cancelable attribute value is true.

The defaultPrevented attribute must return true if the canceled flag is set and false otherwise.


The isTrusted attribute must return the value it was initialized to. When an event is created the attribute must be initialized to false.

The timeStamp attribute must return the value it was initialized to. When an event is created the attribute must be initialized to the number of milliseconds that have passed since 00:00:00 UTC on 1 January 1970, ignoring leap seconds.


To initialize an event, with type, bubbles, and cancelable, run these steps:

  1. Set the initialized flag.

  2. If the dispatch flag is set, terminate these steps.

  3. Unset the stop propagation flag, stop immediate propagation flag, and canceled flag.

  4. Set the isTrusted attribute to false.

  5. Set the target attribute to null.

  6. Set the type attribute to type.

  7. Set the bubbles attribute to bubbles.

  8. Set the cancelable attribute to cancelable.

The initEvent(type, bubbles, cancelable) method must initialize the context object with type, bubbles, and cancelable.

As events have constructors initEvent() is superfluous. However, it has to be supported for legacy content.

4.3 Interface CustomEvent

[Constructor(DOMString type, optional CustomEventInit eventInitDict),
 Exposed=Window,Worker]
interface CustomEvent : Event {
  readonly attribute any detail;

  void initCustomEvent(DOMString type, boolean bubbles, boolean cancelable, any detail);
};

dictionary CustomEventInit : EventInit {
  any detail = null;
};

Events using the CustomEvent interface can be used to carry custom data.

event = new CustomEvent(type [, eventInitDict])

Works analogously to the constructor for Event except that the optional eventInitDict argument now allows for setting the detail attribute too.

event . detail

Returns any custom data event was created with. Typically used for synthetic events.

The detail attribute must return the value it was initialized to. When an event is created the attribute must be initialized to null. The CustomEventInit dictionary is not sufficient due to the existence of the legacy createEvent().

The initCustomEvent(type, bubbles, cancelable, detail) method must initialize the context object with type, bubbles, and cancelable, and then set its detail attribute to detail.

4.4 Constructing events

When a constructor of the Event interface, or of an interface that inherits from the Event interface, is invoked, these steps must be run:

  1. Create an event that uses the interface the constructor was invoked upon.

  2. Set its initialized flag.

  3. Initialize the type attribute to the type argument.

  4. If there is an eventInitDict argument then for each dictionary member defined therein find the attribute on event whose identifier matches the key of the dictionary member and then set the attribute to the value of that dictionary member.

  5. Return the event.

4.5 Defining event interfaces

In general, when defining a new interface that inherits from Event please always ask feedback from the WHATWG or the W3C WebApps WG community.

The CustomEvent interface can be used as starting point. However, do not introduce any init*Event() methods as they are redundant with constructors. Interfaces that inherit from the Event interface that have such a method only have it for historical reasons.

4.6 Interface EventTarget

[Exposed=Window,Worker]
interface EventTarget {
  void addEventListener(DOMString type, EventListener? callback, optional boolean capture = false);
  void removeEventListener(DOMString type, EventListener? callback, optional boolean capture = false);
  boolean dispatchEvent(Event event);
};

callback interface EventListener {
  void handleEvent(Event event);
};

EventTarget is an object to which an event is dispatched when something has occurred. Each EventTarget has an associated list of event listeners.

An event listener associates a callback with a specific event. Each event listener consists of a type (of the event), callback, and capture variable.

The callback is named EventListener for historical reasons. As can be seen from the definition above, an event listener is a more broad concept.

target . addEventListener(type, callback [, capture = false])

Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched. When set to true, the capture argument prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false, callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked when event's eventPhase attribute value is AT_TARGET.

The event listener is appended to target's list of event listeners and is not appended if it is a duplicate (the event listeners in the list are unique).

target . removeEventListener(type, callback [, capture = false])

Remove the event listener in target's list of event listeners with the same type, callback, and capture.

target . dispatchEvent(event)

Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or it's preventDefault() method was not invoked, and false otherwise.

The addEventListener(type, callback, capture) method must run these steps:

  1. If callback is null, terminate these steps.

  2. Append an event listener to the associated list of event listeners with type set to type, callback set to callback, and capture set to capture, unless there already is an event listener in that list with the same type, callback, and capture.

The removeEventListener(type, callback, capture) method must run these steps:

  1. Remove an event listener from the associated list of event listeners, whose type is name, callback is callback, and capture is capture.

The dispatchEvent(event) method must run these steps:

  1. If event's dispatch flag is set, or if its initialized flag is not set, throw an "InvalidStateError" exception.

  2. Initialize event's isTrusted attribute to false.

  3. Dispatch the event and return the value that returns.

4.7 Dispatching events

To dispatch an event to a given object, optionally with a target override, run these steps:

  1. Let event be the event that is dispatched.

  2. Set event's dispatch flag.

  3. Initialize event's target attribute to target override, if it is given, or the object to which event is dispatched otherwise.

  4. If event's target attribute value is participating in a tree, let event path be a static ordered list of all its ancestors in tree order, and let event path be the empty list otherwise.

  5. Initialize event's eventPhase attribute to CAPTURING_PHASE.

  6. For each object in event path, invoke its event listeners with event event, as long as event's stop propagation flag is unset.

  7. Initialize event's eventPhase attribute to AT_TARGET.

  8. Invoke the event listeners of event's target attribute value with event, if event's stop propagation flag is unset.

  9. If event's bubbles attribute value is true, run these substeps:

    1. Reverse the order of event path.

    2. Initialize event's eventPhase attribute to BUBBLING_PHASE.

    3. For each object in event path, invoke its event listeners, with event event as long as event's stop propagation flag is unset.

  10. Unset event's dispatch flag.

  11. Initialize event's eventPhase attribute to NONE.

  12. Initialize event's currentTarget attribute to null.

  13. Return false if event's canceled flag is set, and true otherwise.

To invoke the event listeners for an object with an event run these steps:

  1. Let event be the event for which the event listeners are invoked.

  2. Let listeners be a copy of the event listeners associated with the object for which these steps are run.

  3. Initialize event's currentTarget attribute to the object for which these steps are run.

  4. Then run these substeps for each event listener in listeners:

    1. If event's stop immediate propagation flag is set, terminate the invoke algorithm.

    2. Let listener be the event listener.

    3. If event's type attribute value is not listener's type, terminate these substeps (and run them for the next event listener).

    4. If event's eventPhase attribute value is CAPTURING_PHASE and listener's capture is false, terminate these substeps (and run them for the next event listener).

    5. If event's eventPhase attribute value is BUBBLING_PHASE and listener's capture is true, terminate these substeps (and run them for the next event listener).

    6. Call listener's callback's handleEvent, with the event passed to this algorithm as the first argument and event's currentTarget attribute value as callback this value.

4.8 Firing events

To fire an event named e means that a new event using the Event interface, with its type attribute initialized to e, and its isTrusted attribute initialized to true, is to be dispatched to the given object.

Fire in the context of DOM is short for creating, initializing, and dispatching an event. Fire an event makes that process easier to write down. If the event needs its bubbles or cancelable attribute initialized, one could write "fire an event named submit with its cancelable attribute initialized to true".

5 Nodes

5.1 Introduction to "The DOM"

In its original sense, "The DOM" is an API for accessing and manipulating documents (in particular, HTML and XML documents). In this specification, the term "document" is used for any markup-based resource, ranging from short static documents to long essays or reports with rich multimedia, as well as to fully-fledged interactive applications.

These documents are presented as a node tree. Some of the nodes in the tree can have children, while others are leaves.

To illustrate, consider this HTML document:

<!DOCTYPE html>
<html class=e>
 <head><title>Aliens?</title></head>
 <body>Why yes.</body>
</html>

It is represented as follows:

Note that, due to the magic that is HTML parsing, not all ASCII whitespace were turned into Text nodes, but the general concept is clear. Markup goes in, a tree of nodes comes out.

The most excellent Live DOM Viewer can be used to explore this matter in more detail.

5.2 Node tree

Objects implementing the Document, DocumentFragment, DocumentType, Element, Text, ProcessingInstruction, or Comment interface (simply called nodes) participate in a tree, simply named the node tree.

A node tree is constrained as follows, expressed as a relationship between the type of node and its allowed children:

Document

In tree order:

  1. Zero or more nodes each of which is either ProcessingInstruction or Comment.

  2. Optionally one DocumentType node.

  3. Zero or more nodes each of which is either ProcessingInstruction or Comment.

  4. Optionally one Element node.

  5. Zero or more nodes each of which is either ProcessingInstruction or Comment.

DocumentFragment
Element

Zero or more nodes each of which is one of Element, ProcessingInstruction, Comment, or Text.

DocumentType
Text
ProcessingInstruction
Comment

None.

The length of a node node depends on node:

DocumentType

Zero.

Text
ProcessingInstruction
Comment

Its length attribute value.

Any other node

Its number of children.

A node is considered empty if its length is zero.

5.2.1 Mutation algorithms

At certain points in the algorithms below it is said that a node is inserted or a node is removed. These are hooks for other applicable specifications to process the nodes that have been inserted or removed further and ensures that when multiple nodes are inserted or removed this happens atomically.

To pre-insert a node into a parent before a child, run these steps:

  1. If parent is not a Document, DocumentFragment, or Element node, throw a "HierarchyRequestError".

  2. If node is a host-including inclusive ancestor of parent, throw a "HierarchyRequestError".

  3. If child is not null and its parent is not parent, throw a "NotFoundError" exception.

  4. If node is not a DocumentFragment, DocumentType, Element, Text, ProcessingInstruction, or Comment node, throw a "HierarchyRequestError".

  5. If either node is a Text node and parent is a document, or node is a doctype and parent is not a document, throw a "HierarchyRequestError".

  6. If parent is a document, and any of the statements below, switched on node, are true, throw a "HierarchyRequestError".

    DocumentFragment node

    If node has more than one element child or has a Text node child.

    Otherwise, if node has one element child, and parent has an element child, child is a doctype, or child is not null and a doctype is following child.

    element

    parent has an element child, child is a doctype, or child is not null and a doctype is following child.

    doctype

    parent has a doctype child, an element is preceding child, or child is null and parent has an element child.

  7. Let reference child be child.

  8. If reference child is node, set it to node's next sibling.

  9. Adopt node into parent's node document.

  10. Insert node into parent before reference child.

  11. Return node.

To insert a node into a parent before a child, optionally with a suppress observers flag, run these steps:

  1. Let count be the number of children of node if it is a DocumentFragment node, and one otherwise.

  2. For each range whose start node is parent and start offset is greater than child's index, increase its start offset by count.

  3. For each range whose end node is parent and end offset is greater than child's index, increase its end offset by count.

  4. Let nodes be node's children if node is a DocumentFragment node, and a list containing solely node otherwise.

  5. If node is a DocumentFragment node, queue a mutation record of "childList" for node with removedNodes nodes.

    This step does intentionally not pay attention to the suppress observers flag.

  6. If node is a DocumentFragment node, remove its children with the suppress observers flag set.

  7. If suppress observers flag is unset, queue a mutation record of "childList" for parent with addedNodes nodes, nextSibling child, and previousSibling child's previous sibling or parent's last child if child is null.

  8. Insert all nodes in nodes before child or at the end of parent if child is null.

  9. If suppress observers flag is unset, for each node in nodes, in tree order run node is inserted.

To append a node to a parent, pre-insert node into parent before null.

To replace a child with node within a parent, run these steps:

  1. If parent is not a Document, DocumentFragment, or Element node, throw a "HierarchyRequestError".

  2. If node is a host-including inclusive ancestor of parent, throw a "HierarchyRequestError".

  3. If child's parent is not parent, throw a "NotFoundError" exception.

  4. If node is not a DocumentFragment, DocumentType, Element, Text, ProcessingInstruction, or Comment node, throw a "HierarchyRequestError".

  5. If either node is a Text node and parent is a document, or node is a doctype and parent is not a document, throw a "HierarchyRequestError".

  6. If parent is a document, and any of the statements below, switched on node, are true, throw a "HierarchyRequestError".

    DocumentFragment node

    If node has more than one element child or has a Text node child.

    Otherwise, if node has one element child and either parent has an element child that is not child or a doctype is following child.

    element

    parent has an element child that is not child or a doctype is following child.

    doctype
    parent has a doctype child that is not child, or an element is preceding child.

    The above statements differ from the pre-insert algorithm.

  7. Let reference child be child's next sibling.

  8. If reference child is node, set it to node's next sibling.

  9. Adopt node into parent's node document.

  10. Remove child from its parent with the suppress observers flag set.

  11. Insert node into parent before reference child with the suppress observers flag set.

  12. Let nodes be node's children if node is a DocumentFragment node, and a list containing solely node otherwise.

  13. Queue a mutation record of "childList" for target parent with addedNodes nodes, removedNodes a list solely containing child, nextSibling reference child, and previousSibling child's previous sibling.

  14. Run node is removed for child, and then for each node in nodes, in tree order, run node is inserted.

  15. Return child.

To replace all with a node within a parent, run these steps:

  1. If node is not null, adopt node into parent's node document.

  2. Let removedNodes be parent's children.

  3. Let addedNodes be the empty list if node is null, node's children if node is a DocumentFragment node, and a list containing node otherwise.

  4. Remove all parent's children, with the suppress observers flag set.

  5. If node is not null, insert node into parent before null with the suppress observers flag set.

  6. Queue a mutation record of "childList" for parent with addedNodes addedNodes and removedNodes removedNodes.

  7. Run node is removed for each node in removedNodes, in tree order, and then run node is inserted for each node in addedNodes, in tree order.

This algorithm does not make any checks with regards to the node tree constraints. Use it wisely.

To pre-remove a child from a parent, run these steps:

  1. If child's parent is not parent, throw a "NotFoundError" exception.

  2. Remove child from parent.

  3. Return child.

To remove a node from a parent, optionally with suppress observers flag set, run these steps:

  1. Let index be node's index.

  2. For each range whose start node is a descendant of node, set its start to (parent, index).

  3. For each range whose end node is a descendant of node, set its end to (parent, index).

  4. For each range whose start node is parent and start offset is greater than index, decrease its start offset by one.

  5. For each range whose end node is parent and end offset is greater than index, decrease its end offset by one.

  6. If suppress observers flag is unset, queue a mutation record of "childList" for parent with removedNodes a list solely containing node, nextSibling node's next sibling, and previousSibling node's previous sibling.

  7. For each ancestor ancestor of node, if ancestor has any registered observers whose options's subtree is true, then for each such registered observer registered, append a transient registered observer whose observer and options are identical to those of registered and source which is registered to node's list of registered observers.

  8. Remove node from its parent.

  9. If suppress observers flag is unset, run node is removed for node.

5.2.2 Interface NonElementParentNode

The getElementById() method is not on elements for compatibility with older versions of jQuery. If a time comes where that version of jQuery has disappeared, we might be able to support it.

[NoInterfaceObject]
interface NonElementParentNode {
  Element? getElementById(DOMString elementId);
};
Document implements NonElementParentNode;
DocumentFragment implements NonElementParentNode;
node . getElementById(elementId)

Returns the first element within node's descendants whose ID is elementId.

The getElementById(elementId) method must return the first element, in tree order, within context object's descendants, whose ID is elementId, and null if there is no such element otherwise.

5.2.3 Interface ParentNode

The mutation method macro:

  1. Let node be null.

  2. Replace each string in nodes with a Text node whose data is the string value.

  3. If nodes contains more than one node, set node to a new DocumentFragment and append each node in nodes to it. If this throws an exception, re-throw the exception.

    Otherwise, set node to the single node nodes contains.

[NoInterfaceObject]
interface ParentNode {
  readonly attribute HTMLCollection children;
  readonly attribute Element? firstElementChild;
  readonly attribute Element? lastElementChild;
  readonly attribute unsigned long childElementCount;

  Element? querySelector(DOMString selectors);
  [NewObject] NodeList querySelectorAll(DOMString selectors);
};
Document implements ParentNode;
DocumentFragment implements ParentNode;
Element implements ParentNode;
collection = node . children

Returns the child elements.

element = node . firstElementChild

Returns the first child that is an element, and null otherwise.

element = node . lastElementChild

Returns the last child that is an element, and null otherwise.

node . querySelector(selectors)

Returns the first element that is a descendant of node that matches selectors.

node . querySelectorAll(selectors)

Returns all element descendants of node that match selectors.

The children attribute must return an HTMLCollection collection rooted at the context object matching only element children.

The firstElementChild attribute must return the first child that is an element, and null otherwise.

The lastElementChild attribute must return the last child that is an element, and null otherwise.

The childElementCount attribute must return the number of children of the context object that are elements.

To scope-match a selectors string selectors against a node, run these steps:

  1. Let s be the result of parse a selector selectors. [SELECTORS]

  2. If s is failure, throw a JavaScript TypeError.

  3. Return the result of evaluate a selector s against node's root using scoping root node and scoping method scope-filtered. [SELECTORS].

The querySelector(selectors) method must return the first result of running scope-match a selectors string selectors against the context object, and null if the result is an empty list otherwise.

The querySelectorAll(selectors) method must return the static result of running scope-match a selectors string selectors against the context object.

5.2.4 Interface NonDocumentTypeChildNode

The previousElementSibling and nextElementSibling attributes have been removed from DocumentType nodes for compatibility reasons. If these additions are deemed compatible enough in the future, they could be reinstated.

[NoInterfaceObject]
interface NonDocumentTypeChildNode {
  readonly attribute Element? previousElementSibling;
  readonly attribute Element? nextElementSibling;
};
Element implements NonDocumentTypeChildNode;
CharacterData implements NonDocumentTypeChildNode;
element = node . previousElementSibling

Returns the first preceding sibling that is an element, and null otherwise.

element = node . nextElementSibling

Returns the first following sibling that is an element, and null otherwise.

The previousElementSibling attribute must return the first preceding sibling that is an element, and null otherwise.

The nextElementSibling attribute must return the first following sibling that is an element, and null otherwise.

5.2.5 Interface ChildNode

[NoInterfaceObject]
interface ChildNode {
  void remove();
};
DocumentType implements ChildNode;
Element implements ChildNode;
CharacterData implements ChildNode;
node . remove()

Removes node.

The remove() method must run these steps:

  1. If the context object does not have a parent, terminate these steps.

  2. Remove the context object from the context object's parent.

5.2.6 Old-style collections: NodeList and HTMLCollection

A collection is an object that represents a lists of DOM nodes. A collection can be either live or static. Unless otherwise stated, a collection must be live.

If a collection is live, then the attributes and methods on that object must operate on the actual underlying data, not a snapshot of the data.

When a collection is created, a filter and a root are associated with it.

The collection then represents a view of the subtree rooted at the collection's root, containing only nodes that match the given filter. The view is linear. In the absence of specific requirements to the contrary, the nodes within the collection must be sorted in tree order.

5.2.6.1 Interface NodeList

A NodeList object is a collection of nodes.

interface NodeList {
  getter Node? item(unsigned long index);
  readonly attribute unsigned long length;
};
collection . length

Returns the number of nodes in the collection.

element = collection . item(index)
element = collection[index]

Returns the node with index index from the collection. The nodes are sorted in tree order.

The object's supported property indices are the numbers in the range zero to one less than the number of nodes represented by the collection. If there are no such elements, then there are no supported property indices.

The length attribute must return the number of nodes represented by the collection.

The item(index) method must return the indexth node in the collection. If there is no indexth node in the collection, then the method must return null.

5.2.6.2 Interface HTMLCollection
interface HTMLCollection {
  readonly attribute unsigned long length;
  getter Element? item(unsigned long index);
  getter Element? namedItem(DOMString name);
};

An HTMLCollection object is a collection of elements.

collection . length

Returns the number of elements in the collection.

element = collection . item(index)
element = collection[index]

Returns the element with index index from the collection. The elements are sorted in tree order.

element = collection . namedItem(name)
element = collection[name]

Returns the first element with ID or name name from the collection.

The object's supported property indices are the numbers in the range zero to one less than the number of nodes represented by the collection. If there are no such elements, then there are no supported property indices.

The length attribute must return the number of nodes represented by the collection.

The item(index) method must return the indexth element in the collection. If there is no indexth element in the collection, then the method must return null.

The supported property names, all unenumerable, are the values from the list returned by these steps:

  1. Let result be an empty list.

  2. For each element represented by the collection, in tree order, run these substeps:

    1. If element has an ID which is neither the empty string nor is in result, append element's ID to result.

    2. If element is in the HTML namespace and has a name attribute whose value is neither the empty string nor is in result, append element's name attribute value to result.

  3. Return result.

The namedItem(key) method must run these steps:

  1. If key is the empty string, return null.
  2. Return the first element in the collection for which at least one of the following is true:

    or null if there is no such element.

5.3 Mutation observers

Each unit of related similar-origin browsing contexts has a mutation observer compound microtask queued flag and an associated list of MutationObserver objects which is initially empty. [HTML]

To queue a mutation observer compound microtask, run these steps:

  1. If mutation observer compound microtask queued flag is set, terminate these steps.

  2. Set mutation observer compound microtask queued flag.

  3. Queue a compound microtask to notify mutation observers.

To notify mutation observers, run these steps:

  1. Unset mutation observer compound microtask queued flag.

  2. Let notify list be a copy of unit of related similar-origin browsing contexts's list of MutationObserver objects.

  3. For each MutationObserver object mo in notify list, execute a compound microtask subtask to run these steps: [HTML]

    1. Let queue be a copy of mo's record queue.

    2. Empty mo's record queue.

    3. Remove all transient registered observers whose observer is mo.

    4. If queue is non-empty, invoke mo's callback with queue as first argument, and mo (itself) as second argument and callback this value.


Each node has an associated list of registered observers.

A registered observer consists of an observer (a MutationObserver object) and options (a MutationObserverInit dictionary). A transient registered observer is a specific type of registered observer that has a source which is a registered observer.

5.3.1 Interface MutationObserver

[Constructor(MutationCallback callback)]
interface MutationObserver {
  void observe(Node target, MutationObserverInit options);
  void disconnect();
  sequence<MutationRecord> takeRecords();
};

callback MutationCallback = void (sequence<MutationRecord> mutations, MutationObserver observer);

dictionary MutationObserverInit {
  boolean childList = false;
  boolean attributes;
  boolean characterData;
  boolean subtree = false;
  boolean attributeOldValue;
  boolean characterDataOldValue;
  sequence<DOMString> attributeFilter;
};

A MutationObserver object can be used to observe mutations to the tree of nodes.

Each MutationObserver object has these associated concepts:

observer = new MutationObserver(callback)

Constructs a MutationObserver object and sets its callback to callback. The callback is invoked with a list of MutationRecord objects as first argument and the constructed MutationObserver object as second argument. It is invoked after nodes registered with the observe() method, are mutated.

observer . observe(target, options)

Instructs the user agent to observe a given target (a node) and report any mutations based on the criteria given by options (an object).

The options argument allows for setting mutation observation options via object members. These are the object members that can be used:

childList

Set to true if mutations to target's children are to be observed.

attributes

Set to true if mutations to target's attributes are to be observed. Can be omitted if attributeOldValue and/or attributeFilter is specified.

characterData

Set to true if mutations to target's data are to be observed. Can be omitted if characterDataOldValue is specified.

subtree

Set to true if mutations to not just target, but also target's descendants are to be observed.

attributeOldValue

Set to true if attributes is true or omitted and target's attribute value before the mutation needs to be recorded.

characterDataOldValue

Set to true if characterData is set to true or omitted and target's data before the mutation needs to be recorded.

attributeFilter

Set to a list of attribute local names (without namespace) if not all attribute mutations need to be observed and attributes is true or omitted.

observer . disconnect()

Stops observer from observing any mutations. Until the observe() method is used again, observer's callback will not be invoked.

observer . takeRecords()

Empties the record queue and returns what was in there.

The MutationObserver(callback) constructor must create a new MutationObserver object with callback set to callback, append it to the unit of related similar-origin browsing contexts's list of MutationObserver objects, and then return it.

The observe(target, options) method must run these steps:

  1. If either options' attributeOldValue or attributeFilter is present and options' attributes is omitted, set options' attributes to true.

  2. If options' characterDataOldValue is present and options' characterData is omitted, set options' characterData to true.

  3. If options' attributeOldValue is true and options' attributes is false, throw a JavaScript TypeError.

  4. If options' attributeFilter is present and options' attributes is false, throw a JavaScript TypeError.

  5. If options' characterDataOldValue is true and options' characterData is false, throw a JavaScript TypeError.

  6. For each registered observer registered in target's list of registered observers whose observer is the context object:

    1. Remove all transient registered observers whose source is registered.

    2. Replace registered's options with options.

  7. Otherwise, add a new registered observer to target's list of registered observers with the context object as the observer and options as the options, and add target to context object's list of nodes on which it is registered.

The disconnect() method must, for each node node in the context object's list of nodes, remove any registered observer on node for which the context object is the observer, and also empty context object's record queue.

The takeRecords() method must return a copy of the record queue and then empty the record queue.

5.3.2 Queuing a mutation record

To queue a mutation record of type for target with one or more of (depends on type) name name, namespace namespace, oldValue oldValue, addedNodes addedNodes, removedNodes removedNodes, previousSibling previousSibling, and nextSibling nextSibling, run these steps:

  1. Let interested observers be an initially empty set of MutationObserver objects optionally paired with a string.

  2. Let nodes be the inclusive ancestors of target.

  3. Then, for each node in nodes, and then for each registered observer (with registered observer's options as options) in node's list of registered observers:

    1. If node is not target and options's subtree is false, continue.

    2. If type is "attributes" and options's attributes is not true, continue.

    3. If type is "attributes", options's attributeFilter is present, and either options's attributeFilter does not contain name or namespace is non-null, continue.

    4. If type is "characterData" and options's characterData is not true, continue.

    5. If type is "childList" and options's childList is false, continue.

    6. If registered observer's observer is not in interested observers, append registered observer's observer to interested observers.

    7. If either type is "attributes" and options's attributeOldValue is true, or type is "characterData" and options's characterDataOldValue is true, set the paired string of registered observer's observer in interested observers to oldValue.

  4. Then, for each observer in interested observers:

    1. Let record be a new MutationRecord object with its type set to type and target set to target.

    2. If name and namespace are given, set record's attributeName to name, and record's attributeNamespace to namespace.

    3. If addedNodes is given, set record's addedNodes to addedNodes.

    4. If removedNodes is given, set record's removedNodes to removedNodes,

    5. If previousSibling is given, set record's previousSibling to previousSibling.

    6. If nextSibling is given, set record's nextSibling to nextSibling.

    7. If observer has a paired string, set record's oldValue to observer's paired string.

    8. Append record to observer's record queue.

  5. Queue a mutation observer compound microtask.

5.3.3 Interface MutationRecord

interface MutationRecord {
  readonly attribute DOMString type;
  readonly attribute Node target;
  [SameObject] readonly attribute NodeList addedNodes;
  [SameObject] readonly attribute NodeList removedNodes;
  readonly attribute Node? previousSibling;
  readonly attribute Node? nextSibling;
  readonly attribute DOMString? attributeName;
  readonly attribute DOMString? attributeNamespace;
  readonly attribute DOMString? oldValue;
};
record . type

Returns "attributes" if it was an attribute mutation. "characterData" if it was a mutation to a CharacterData node. And "childList" if it was a mutation to the tree of nodes.

record . target

Returns the node the mutation affected, depending on the type. For "attributes", it is the element whose attribute changed. For "characterData", it is the CharacterData node. For "childList", it is the node whose children changed.

record . addedNodes
record . removedNodes

Return the nodes added and removed respectively.

record . previousSibling
record . nextSibling

Return the previous and next sibling respectively of the added or removed nodes, and null otherwise.

record . attributeName

Returns the local name of the changed attribute, and null otherwise.

record . attributeNamespace

Returns the namespace of the changed attribute, and null otherwise.

record . oldValue

The return value depends on type. For "attributes", it is the value of the changed attribute before the change. For "characterData", it is the data of the changed node before the change. For "childList", it is null.

The type and target attributes must return the values they were initialized to.

The addedNodes and removedNodes attributes must return the values they were initialized to. Unless stated otherwise, when a MutationRecord object is created, they must both be initialized to an empty NodeList.

The previousSibling, nextSibling, attributeName, attributeNamespace, and oldValue attributes must return the values they were initialized to. Unless stated otherwise, when a MutationRecord object is created, they must be initialized to null.

5.3.4 Garbage collection

Nodes have a strong reference to registered observers in their list of registered observers.

Registered observers in a node's list of registered observers have a weak reference to the node.

5.4 Interface Node

interface Node : EventTarget {
  const unsigned short ELEMENT_NODE = 1;
  const unsigned short ATTRIBUTE_NODE = 2; // historical
  const unsigned short TEXT_NODE = 3;
  const unsigned short CDATA_SECTION_NODE = 4; // historical
  const unsigned short ENTITY_REFERENCE_NODE = 5; // historical
  const unsigned short ENTITY_NODE = 6; // historical
  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; // historical
  readonly attribute unsigned short nodeType;
  readonly attribute DOMString nodeName;

  readonly attribute DOMString? baseURI;

  readonly attribute Document? ownerDocument;
  readonly attribute Node? parentNode;
  readonly attribute Element? parentElement;
  boolean hasChildNodes();
  [SameObject] readonly attribute NodeList childNodes;
  readonly attribute Node? firstChild;
  readonly attribute Node? lastChild;
  readonly attribute Node? previousSibling;
  readonly attribute Node? nextSibling;

           attribute DOMString? nodeValue;
           attribute DOMString? textContent;
  void normalize();

  Node cloneNode(optional boolean deep = false);
  boolean isEqualNode(Node? node);

  const unsigned short DOCUMENT_POSITION_DISCONNECTED = 0x01;
  const unsigned short DOCUMENT_POSITION_PRECEDING = 0x02;
  const unsigned short DOCUMENT_POSITION_FOLLOWING = 0x04;
  const unsigned short DOCUMENT_POSITION_CONTAINS = 0x08;
  const unsigned short DOCUMENT_POSITION_CONTAINED_BY = 0x10;
  const unsigned short DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC = 0x20;
  unsigned short compareDocumentPosition(Node other);
  boolean contains(Node? other);

  DOMString? lookupPrefix(DOMString? namespace);
  DOMString? lookupNamespaceURI(DOMString? prefix);
  boolean isDefaultNamespace(DOMString? namespace);

  Node insertBefore(Node node, Node? child);
  Node appendChild(Node node);
  Node replaceChild(Node node, Node child);
  Node removeChild(Node child);
};

Node is an abstract interface and does not exist as node. It is used by all nodes (Document, DocumentFragment, DocumentType, Element, Text, ProcessingInstruction, and Comment).

Each node has an associated node document, set upon creation, that is a document.

A node's node document can be changed by the adopt algorithm.

Each node also has an associated base URL.

Other specifications define the value of the base URL and its observable behavior. This specification solely defines the concept and the baseURI attribute.


node . nodeType

Returns the type of node, represented by a number from the following list:

Node . ELEMENT_NODE (1)
node is an element.
Node . TEXT_NODE (3)
node is a Text node.
Node . PROCESSING_INSTRUCTION_NODE (7)
node is a ProcessingInstruction node.
Node . COMMENT_NODE (8)
node is a Comment node.
Node . DOCUMENT_NODE (9)
node is a document.
Node . DOCUMENT_TYPE_NODE (10)
node is a doctype.
Node . DOCUMENT_FRAGMENT_NODE (11)
node is a DocumentFragment node.
node . nodeName

Returns a string appropriate for the type of node, as follows:

Element
Its tagName attribute value.
Text
"#text".
ProcessingInstruction
Its target.
Comment
"#comment".
Document
"#document".
DocumentType
Its name.
DocumentFragment
"#document-fragment".

The nodeType attribute must return the type of the node, which must be one of the following:

The nodeName attribute must return the following, depending on the context object:

Element

Its tagName attribute value.

Text

"#text".

ProcessingInstruction

Its target.

Comment

"#comment".

Document

"#document".

DocumentType

Its name.

DocumentFragment

"#document-fragment".


node . baseURI

Returns the base URL.

The baseURI attribute must return the associated base URL.


node . ownerDocument

Returns the node document.

Returns null for documents.

node . parentNode

Returns the parent.

node . parentElement

Returns the parent element.

node . hasChildNodes()

Returns whether node has children.

node . childNodes

Returns the children.

node . firstChild

Returns the first child.

node . lastChild

Returns the last child.

node . previousSibling

Returns the previous sibling.

node . nextSibling

Returns the next sibling.

The ownerDocument attribute must run these steps:

  1. If the context object is a document, return null.
  2. Return the node document.

The node document of a document is that document itself.

All nodes have a document at all times.

The parentNode attribute must return the parent.

The parentElement attribute must return the parent element.

The hasChildNodes() method must return true if the context object has children, and false otherwise.

The childNodes attribute must return a NodeList rooted at the context object matching only children.

The firstChild attribute must return the first child.

The lastChild attribute must return the last child.

The previousSibling attribute must return the previous sibling.

The nextSibling attribute must return the next sibling.


The nodeValue attribute must return the following, depending on the context object:

Text
Comment
ProcessingInstruction

The context object's data.

Any other node

Null.

The nodeValue attribute must, on setting, if the new value is null, act as if it was the empty string instead, and then do as described below, depending on the context object:

Text
Comment
ProcessingInstruction

Replace data with node context object, offset 0, count length attribute value, and data new value.

Any other node

Do nothing.

The textContent attribute must return the following, depending on the context object:

DocumentFragment
Element

The concatenation of data of all the Text node descendants of the context object, in tree order.

Text
ProcessingInstruction
Comment

The context object's data.

Any other node

Null.

The textContent attribute must, on setting, if the new value is null, act as if it was the empty string instead, and then do as described below, depending on the context object:

DocumentFragment
Element
  1. Let node be null.

  2. If new value is not the empty string, set node to a new Text node whose data is new value.

  3. Replace all with node within the context object.

Text
ProcessingInstruction
Comment

Replace data with node context object, offset 0, count length attribute value, and data new value.

Any other node

Do nothing.


node . normalize()

Removes empty Text nodes and concatenates the data of remaining contiguous Text nodes into the first of their nodes.

The normalize() method must run these steps:

For each Text node descendant of the context object:

  1. Let node be the Text node descendant.

  2. Let length be node's length attribute value.

  3. If length is zero, remove node and continue with the next Text node, if any.

  4. Let data be the concatenation of the data of node's contiguous Text nodes (excluding itself), in tree order.

  5. Replace data with node node, offset length, count 0, and data data.

  6. Let current node be node's next sibling.

  7. While current node is a Text node:

    1. For each range whose start node is current node, add length to its start offset and set its start node to node.

    2. For each range whose end node is current node, add length to its end offset and set its end node to node.

    3. For each range whose start node is current node's parent and start offset is current node's index, set its start node to node and its start offset to length.

    4. For each range whose end node is current node's parent and end offset is current node's index, set its end node to node and its end offset to length.

    5. Add current node's length attribute value to length.

    6. Set current node to its next sibling.

  8. Remove node's contiguous Text nodes (excluding itself), in tree order.


node . cloneNode([deep = false])

Returns a copy of node. If deep is true, the copy also includes the node's descendants.

node . isEqualNode(other)

Returns whether node and other have the same properties.

Specifications may define cloning steps for all or some nodes. The algorithm is passed copy, node, document, and optionally a clone children flag, as indicated in the clone algorithm.

HTML defines cloning steps for script and input elements. SVG ought to do the same for its script elements, but does not call this out at the moment.

To clone a node, optionally with a document and a clone children flag, run these steps:

  1. If document is not given, let document be node's node document.

  2. Let copy be a node that implements the same interfaces as node.

  3. If copy is a document, set its node document and document to copy.

    Otherwise, set copy's node document to document.

  4. Copy the following from node to copy, depending on the type of node:

    Document

    Its encoding, content type, URL, its mode (quirks mode, limited quirks mode, or no-quirks mode), and its type (XML document or HTML document).

    DocumentType

    Its name, public ID, and system ID.

    Element

    Its namespace, namespace prefix, local name, and its attribute list.

    Text
    Comment

    Its data.

    ProcessingInstruction

    Its target and data.

    Any other node

  5. Run any cloning steps defined for node in other applicable specifications and pass copy, node, document and the clone children flag if set, as parameters.

  6. If the clone children flag is set, clone all the children of node and append them to copy, with document as specified and the clone children flag being set.

  7. Return copy.

The cloneNode(deep) method must return a clone of the context object, with the clone children flag set if deep is true.

A node A equals a node B if all of the following conditions are true:

The isEqualNode(node) method must return true if node is not null and context object equals node, and false otherwise.


node . compareDocumentPosition(other)

Returns a bitmask indicating the position of other relative to node. These are the bits that can be set:

Node . DOCUMENT_POSITION_DISCONNECTED (1)
Set when node and other are not in the same tree.
Node . DOCUMENT_POSITION_PRECEDING (2)
Set when other is preceding node.
Node . DOCUMENT_POSITION_FOLLOWING (4)
Set when other is following node.
Node . DOCUMENT_POSITION_CONTAINS (8)
Set when other is an ancestor of node.
Node . DOCUMENT_POSITION_CONTAINED_BY (16, 10 in hexadecimal)
Set when other is a descendant of node.
node . contains(other)

Returns true if other is an inclusive descendant of node, and false otherwise.

These are the constants compareDocumentPosition() returns as mask:

The compareDocumentPosition(other) method must run these steps:

  1. Let reference be the context object.

  2. If other and reference are the same object, return zero.

  3. If other and reference are not in the same tree, return the result of adding DOCUMENT_POSITION_DISCONNECTED, DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC, and either DOCUMENT_POSITION_PRECEDING or DOCUMENT_POSITION_FOLLOWING, with the constraint that this is to be consistent, together.

    Whether to return DOCUMENT_POSITION_PRECEDING or DOCUMENT_POSITION_FOLLOWING is typically implemented via pointer comparison. In JavaScript implementations Math.random() can be used.

  4. If other is an ancestor of reference, return the result of adding DOCUMENT_POSITION_CONTAINS to DOCUMENT_POSITION_PRECEDING.

  5. If other is a descendant of reference, return the result of adding DOCUMENT_POSITION_CONTAINED_BY to DOCUMENT_POSITION_FOLLOWING.

  6. If other is preceding reference return DOCUMENT_POSITION_PRECEDING.

  7. Return DOCUMENT_POSITION_FOLLOWING.

The contains(other) method must return true if other is an inclusive descendant of the context object, and false otherwise (including when other is null).


To locate a namespace prefix for an element using namespace run these steps:

  1. If element's namespace is namespace and its namespace prefix is not null, return its namespace prefix.

  2. If, element has an attribute whose namespace prefix is "xmlns" and value is namespace, then return element's first such attribute's local name.

  3. If element's parent element is not null, return the result of running locate a namespace prefix on that element using namespace. Otherwise, return null.

To locate a namespace for a node using prefix depends on node:

Element
  1. If its namespace is not null and its namespace prefix is prefix, return namespace.

  2. If it has an attribute whose namespace is the XMLNS namespace, namespace prefix is "xmlns" and local name is prefix, or if prefix is null and it has an attribute whose namespace is the XMLNS namespace, namespace prefix is null and local name is "xmlns":

    1. Let value be its value if it is not the empty string, and null otherwise.

    2. Return value.

  3. If its parent element is null, return null.

  4. Return the result of running locate a namespace on its parent element using prefix.

Document
  1. If its document element is null, return null.

  2. Return the result of running locate a namespace on its document element using prefix.

DocumentType
DocumentFragment

Return null.

Any other node
  1. If its parent element is null, return null.

  2. Return the result of running locate a namespace on its parent element using prefix.

The lookupPrefix(namespace) method must run these steps:

  1. If namespace is null or the empty string, return null.

  2. Otherwise it depends on the context object:

    Element

    Return the result of locating a namespace prefix for the node using namespace.

    Document

    Return the result of locating a namespace prefix for its document element, if that is not null, and null otherwise.

    DocumentType
    DocumentFragment

    Return null.

    Any other node

    Return the result of locating a namespace prefix for its parent element, or if that is null, null.

The lookupNamespaceURI(prefix) method must run these steps:

  1. If prefix is the empty string, set it to null.

  2. Return the result of running locate a namespace for the context object using prefix.

The isDefaultNamespace(namespace) method must run these steps:

  1. If namespace is the empty string, set it to null.

  2. Let defaultNamespace be the result of running locate a namespace for the context object using null.

  3. Return true if defaultNamespace is the same as namespace, and false otherwise.


The insertBefore(node, child) method must return the result of pre-inserting node into the context object before child.

The appendChild(node) method must return the result of appending node to the context object.

The replaceChild(node, child) method must return the result of replacing child with node within the context object.

The removeChild(child) method must return the result of pre-removing child from the context object.


The list of elements with local name localName for a node root is the HTMLCollection returned by the following algorithm:

  1. If localName is "*" (U+002A), return a HTMLCollection rooted at root, whose filter matches only elements.

  2. Otherwise, if root's node document is an HTML document, return a HTMLCollection rooted at root, whose filter matches only the following elements:

  3. Otherwise, return a HTMLCollection rooted at root, whose filter matches only elements whose local name is localName.

When invoked with the same argument, the same HTMLCollection object may be returned as returned by an earlier call.

The list of elements with namespace namespace and local name localName for a node root is the HTMLCollection returned by the following algorithm:

  1. If namespace is the empty string, set it to null.

  2. If both namespace and localName are "*" (U+002A) return a HTMLCollection rooted at root, whose filter matches only elements.

  3. Otherwise, if just namespace is "*" (U+002A), return a HTMLCollection rooted at root, whose filter matches only elements whose local name is localName.

  4. Otherwise, if just localName is "*" (U+002A), return a HTMLCollection rooted at root, whose filter matches only elements whose namespace is namespace.

  5. Otherwise, return a HTMLCollection rooted at root, whose filter matches only elements whose namespace is namespace and local name is localName.

When invoked with the same arguments, the same HTMLCollection object may be returned as returned by an earlier call.

The list of elements with class names classNames for a node root is the HTMLCollection returned by the following algorithm:

  1. Let classes be the result of running the ordered set parser on classNames.

  2. If classes is the empty set, return an empty HTMLCollection.

  3. Return a HTMLCollection rooted at root, whose filter matches only elements that have all the classes in classes.

    If root's node document is in quirks mode, then the comparisons for the classes must be done in an ASCII case-insensitive manner, and in a case-sensitive manner otherwise.

When invoked with the same argument, the same HTMLCollection object may be returned as returned by an earlier call.

5.5 Interface Document

[Constructor]
interface Document : Node {
  [SameObject] readonly attribute DOMImplementation implementation;
  readonly attribute DOMString URL;
  readonly attribute DOMString documentURI;
  readonly attribute DOMString compatMode;
  readonly attribute DOMString characterSet;
  readonly attribute DOMString contentType;

  readonly attribute DocumentType? doctype;
  readonly attribute Element? documentElement;
  HTMLCollection getElementsByTagName(DOMString localName);
  HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
  HTMLCollection getElementsByClassName(DOMString classNames);

  [NewObject] Element createElement(DOMString localName);
  [NewObject] Element createElementNS(DOMString? namespace, DOMString qualifiedName);
  [NewObject] DocumentFragment createDocumentFragment();
  [NewObject] Text createTextNode(DOMString data);
  [NewObject] Comment createComment(DOMString data);
  [NewObject] ProcessingInstruction createProcessingInstruction(DOMString target, DOMString data);

  Node importNode(Node node, optional boolean deep = false);
  Node adoptNode(Node node);

  [NewObject] Event createEvent(DOMString interface);

  [NewObject] Range createRange();

  // NodeFilter.SHOW_ALL = 0xFFFFFFFF
  [NewObject] NodeIterator createNodeIterator(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
  [NewObject] TreeWalker createTreeWalker(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
};

interface XMLDocument : Document {};

Document nodes are simply known as documents.

Each document has an associated encoding, content type, and URL. [ENCODING] [URL]

Unless stated otherwise, a document's encoding is the utf-8 encoding, its content type is "application/xml", and its URL is "about:blank".

Unless stated otherwise, a document's origin is a globally unique identifier and its effective script origin is an alias of that origin. [HTML]

A document is assumed to be an XML document unless it is flagged as being an HTML document. Whether a document is an HTML document or an XML document affects the behavior of certain APIs.

A document is always set to one of three modes: no-quirks mode, the default; quirks mode, used typically for legacy documents; and limited-quirks mode. Unless stated otherwise, a document must be in no-quirks mode.

The mode is only ever changed from the default if the document is created by the HTML parser, based on the presence, absence, or value of the DOCTYPE string. [HTML]

No-quirks mode was originally known as "standards mode" and limited-quirks mode was once known as "almost standards mode". They have been renamed because their details are now defined by standards. (And because Ian Hickson vetoed their original names on the basis that they are nonsensical.)


document = new Document()

Returns a new document.

document . implementation

Returns document's DOMImplementation object.

document . URL
document . documentURI

Returns document's URL.

document . compatMode

Returns the string "CSS1Compat" if document is in no-quirks mode or limited-quirks mode, and "BackCompat", if document is in quirks mode.

document . characterSet

Returns document's encoding.

document . contentType

Returns document's content type.

The Document() constructor must return a new document whose origin is an alias to the origin of the global object's associated document, and effective script origin is an alias to the effective script origin of the global object's associated document. [HTML]

Unlike createDocument() this constructor does not return an XMLDocument object, but a document (Document object).

The implementation attribute must return the DOMImplementation object that is associated with the document.

The URL and documentURI attributes must return the URL.

The compatMode attribute must return "BackCompat" if the context object is in quirks mode, and "CSS1Compat" otherwise.

The characterSet attribute must return the name of the encoding.

The contentType attribute must return the content type.


document . doctype

Returns the doctype or null if there is none.

document . documentElement

Returns the document element.

collection = document . getElementsByTagName(localName)

If localName is "*" returns a HTMLCollection of all descendant elements.

Otherwise, returns a HTMLCollection of all descendant elements whose local name is localName. (Matches case-insensitively against elements in the HTML namespace within an HTML document.)

collection = document . getElementsByTagNameNS(namespace, localName)

If namespace and localName are "*" returns a HTMLCollection of all descendant elements.

If only namespace is "*" returns a HTMLCollection of all descendant elements whose local name is localName.

If only localName is "*" returns a HTMLCollection of all descendant elements whose namespace is namespace.

Otherwise, returns a HTMLCollection of all descendant elements whose namespace is namespace and local name is localName.

collection = document . getElementsByClassName(classes)
collection = element . getElementsByClassName(classes)

Returns a HTMLCollection of the elements in the object on which the method was invoked (a document or an element) that have all the classes given by classes.

The classes argument is interpreted as a space-separated list of classes.

The doctype attribute must return the child of the document that is a doctype, and null otherwise.

The documentElement attribute must return the document element.

The getElementsByTagName(localName) method must return the list of elements with local name localName for the context object.

Thus, in an HTML document, document.getElementsByTagName("FOO") will match FOO elements that are not in the HTML namespace, and foo elements that are in the HTML namespace, but not FOO elements that are in the HTML namespace.

The getElementsByTagNameNS(namespace, localName) method must return the list of elements with namespace namespace and local name localName for the context object.

The getElementsByClassName(classNames) method must return the list of elements with class names classNames for the context object.

Given the following XHTML fragment:

<div id="example">
  <p id="p1" class="aaa bbb"/>
  <p id="p2" class="aaa ccc"/>
  <p id="p3" class="bbb ccc"/>
</div>

A call to document.getElementById('example').getElementsByClassName('aaa') would return a HTMLCollection with the two paragraphs p1 and p2 in it.

A call to getElementsByClassName('ccc bbb') would only return one node, however, namely p3. A call to document.getElementById('example').getElementsByClassName('bbb  ccc ') would return the same thing.

A call to getElementsByClassName('aaa,bbb') would return no nodes; none of the elements above are in the aaa,bbb class.


element = document . createElement(localName)

Returns an element in the HTML namespace with localName as local name. (In an HTML document localName is lowercased.)

If localName does not match the Name production an "InvalidCharacterError" exception will be thrown.

element = document . createElementNS(namespace, qualifiedName)

Returns an element with namespace namespace. Its namespace prefix will be everything before ":" (U+003E) in qualifiedName or null. Its local name will be everything after ":" (U+003E) in qualifiedName or qualifiedName.

If localName does not match the Name production an "InvalidCharacterError" exception will be thrown.

If one of the following conditions is true a "NamespaceError" exception will be thrown:

documentFragment = document . createDocumentFragment()

Returns a DocumentFragment node.

text = document . createTextNode(data)

Returns a Text node whose data is data.

comment = document . createComment(data)

Returns a Comment node whose data is data.

processingInstruction = document . createProcessingInstruction(target, data)

Returns a ProcessingInstruction node whose target is target and data is data.

If target does not match the Name production an "InvalidCharacterError" exception will be thrown.

If data contains "?>" an "InvalidCharacterError" exception will be thrown.

The element interface for any name and namespace is Element, unless stated otherwise.

The HTML Standard will e.g. define that for html and the HTML namespace, the HTMLHtmlElement interface is used. [HTML]

The createElement(localName) method must run the these steps:

  1. If localName does not match the Name production, throw an "InvalidCharacterError" exception.

  2. If the context object is an HTML document, let localName be converted to ASCII lowercase.

  3. Let interface be the element interface for localName and the HTML namespace.

  4. Return a new element that implements interface, with no attributes, namespace set to the HTML namespace, local name set to localName, and node document set to the context object.

The createElementNS(namespace, qualifiedName) method must run these steps:

  1. If namespace is the empty string, set it to null.

  2. If qualifiedName does not match the Name production, throw an "InvalidCharacterError" exception.

  3. If qualifiedName does not match the QName production, throw a "NamespaceError" exception.

  4. If qualifiedName contains a ":" (U+003E), then split the string on it and let prefix be the part before and localName the part after. Otherwise, let prefix be null and localName be qualifiedName.

  5. If prefix is not null and namespace is null, throw a "NamespaceError" exception.

  6. If prefix is "xml" and namespace is not the XML namespace, throw a "NamespaceError" exception.

  7. If qualifiedName or prefix is "xmlns" and namespace is not the XMLNS namespace, throw a "NamespaceError" exception.

  8. If namespace is the XMLNS namespace and neither qualifiedName nor prefix is "xmlns", throw a "NamespaceError" exception.

  9. Let interface be the element interface for localName and namespace.

  10. Return a new element that implements interface, with no attributes, namespace set to namespace, namespace prefix set to prefix, local name set to localName, and node document set to the context object.

The createDocumentFragment() method must return a new DocumentFragment node with its node document set to the context object.

The createTextNode(data) method must return a new Text node with its data set to data and node document set to the context object.

No check is performed that data consists of characters that match the Char production.

The createComment(data) method must return a new Comment node with its data set to data and node document set to the context object.

No check is performed that data consists of characters that match the Char production or that it contains two adjacent hyphens or ends with a hyphen.

The createProcessingInstruction(target, data) method must run these steps:

  1. If target does not match the Name production, throw an "InvalidCharacterError" exception.

  2. If data contains the string "?>", throw an "InvalidCharacterError" exception.

  3. Return a new ProcessingInstruction node, with target set to target, data set to data, and node document set to the context object.

No check is performed that target contains "xml" or ":", or that data contains characters that match the Char production.


clone = document . importNode(node [, deep = false])

Returns a copy of node. If deep is true, the copy also includes the node's descendants.

If node is a document throws a "NotSupportedError" exception.

node = document . adoptNode(node)

Moves node from another document and returns it.

If node is a document throws a "NotSupportedError" exception.

The importNode(node, deep) method must run these steps:

  1. If node is a document, throw a "NotSupportedError" exception.

  2. Return a clone of node, with context object and the clone children flag set if deep is true.

Specifications may define adopting steps for all or some nodes. The algorithm is passed node and oldDocument, as indicated in the adopt algorithm.

To adopt a node into a document, run these steps:

  1. Let oldDocument be node's node document.

  2. If node's parent is not null, remove node from its parent.

  3. Set node's inclusive descendants's node document to document.

  4. Run any adopting steps defined for node in other applicable specifications and pass node and oldDocument as parameters.

The adoptNode(node) method must run these steps:

  1. If node is a document, throw a "NotSupportedError" exception.

  2. Adopt node into the context object.

  3. Return node.


The createEvent(interface) method must run these steps:

  1. Let event be null.

  2. If interface is an ASCII case-insensitive match for any of the strings in the first column in the following table, let event be the interface in the second column on the same row as the matching string:

    StringInterfaceNotes
    "customevent"CustomEvent
    "event"Event
    "events"
    "htmlevents"
    "mouseevent"MouseEvent[UIEVENTS]
    "mouseevents"
    "uievent"UIEvent
    "uievents"
  3. If event is null, throw a "NotSupportedError".

  4. Return a new event implementing the event interface.

Event constructors can be used instead.


The createRange() method must return a new range with (context object, 0) as its start and end.

The Range() constructor can be used instead.


The createNodeIterator(root, whatToShow, filter) method must run these steps:

  1. Create a NodeIterator object.

  2. Set root and initialize the referenceNode attribute to the root argument.

  3. Initialize the pointerBeforeReferenceNode attribute to true.

  4. Set whatToShow to the whatToShow argument.

  5. Set filter to filter.

  6. Return the newly created NodeIterator object.

The createTreeWalker(root, whatToShow, filter) method must run these steps:

  1. Create a TreeWalker object.

  2. Set root and initialize the currentNode attribute to the root argument.

  3. Set whatToShow to the whatToShow argument.

  4. Set filter to filter.

  5. Return the newly created TreeWalker object.

5.5.1 Interface DOMImplementation

User agents must create a DOMImplementation object whenever a document is created and associate it with that document.

interface DOMImplementation {
  [NewObject] DocumentType createDocumentType(DOMString qualifiedName, DOMString publicId, DOMString systemId);
  [NewObject] XMLDocument createDocument(DOMString? namespace, [TreatNullAs=EmptyString] DOMString qualifiedName, optional DocumentType? doctype = null);
  [NewObject] Document createHTMLDocument(optional DOMString title);

  boolean hasFeature(); // useless; always returns true
};
doctype = document . implementation . createDocumentType(qualifiedName, publicId, systemId)

Returns a doctype, with the given qualifiedName, publicId, and systemId. If qualifiedName does not match the Name production, an "InvalidCharacterError" exception is thrown, and if it does not match the QName production, a "NamespaceError" exception is thrown.

doc = document . implementation . createDocument(namespace, qualifiedName [, doctype = null])

Returns an XMLDocument, with a document element whose local name is qualifiedName and whose namespace is namespace (unless qualifiedName is the empty string), and with doctype, if it is given, as its doctype.

This method throws the same exceptions as the createElementNS method, when invoked with the same arguments.

doc = document . implementation . createHTMLDocument([title])

Returns a document, with a basic tree already constructed including a title element, unless the title argument is omitted.

The createDocumentType(qualifiedName, publicId, systemId) method must run these steps:

  1. If qualifiedName does not match the Name production, throw an "InvalidCharacterError" exception.

  2. If qualifiedName does not match the QName production, throw a "NamespaceError" exception.

  3. Return a new doctype, with qualifiedName as its name, publicId as its public ID, and systemId as its system ID, and with its node document set to the associated document of the context object.

No check is performed that publicId matches the PublicChar production or that systemId does not contain both a '"' and "'".

The createDocument(namespace, qualifiedName, doctype) method must run these steps:

  1. Let document be a new XMLDocument.

    This method creates an XMLDocument rather than a normal document. They are identical except for the addition of the load() method deployed content relies upon. [HTML]

  2. Let element be null.

  3. If qualifiedName is not the empty string, set element to the result of invoking the createElementNS() method with the arguments namespace and qualifiedName on document. If that threw an exception, re-throw the exception.

  4. If doctype is not null, append doctype to document.

  5. If element is not null, append element to document.

  6. document's origin is an alias to the origin of the context object's associated document, and document's effective script origin is an alias to the effective script origin of the context object's associated document. [HTML]

  7. Return document.

The createHTMLDocument(title) method must run these steps:

  1. Let doc be a new document that is an HTML document.

  2. Set doc's content type to "text/html".

  3. Create a doctype, with "html" as its name and with its node document set to doc. Append the newly created node to doc.

  4. Create an html element in the HTML namespace, and append it to doc.

  5. Create a head element in the HTML namespace, and append it to the html element created in the previous step.

  6. If the title argument is not omitted:

    1. Create a title element in the HTML namespace, and append it to the head element created in the previous step.

    2. Create a Text node, set its data to title (which could be the empty string), and append it to the title element created in the previous step.

  7. Create a body element in the HTML namespace, and append it to the html element created in the earlier step.

  8. doc's origin is an alias to the origin of the context object's associated document, and doc's effective script origin is an alias to the effective script origin of the context object's associated document. [HTML]

  9. Return doc.

The hasFeature() method must return true.

hasFeature() originally would report whether the user agent claimed to support a given DOM feature, but experience proved it was not nearly as reliable or granular as simply checking whether the desired objects, attributes, or methods existed. As such, it should no longer be used, but continues to exist (and simply returns true) so that old pages don't stop working.

5.6 Interface DocumentFragment

[Constructor]
interface DocumentFragment : Node {
};

A DocumentFragment node can have an associated element named host.

An object A is a host-including inclusive ancestor of an object B, if either A is an inclusive ancestor of B, or if B's root has an associated host and A is a host-including inclusive ancestor of B's root's host.

The DocumentFragment node's host concept is useful for HTML's template element and the ShadowRoot object and impacts the pre-insert and replace algorithms.

tree = new DocumentFragment()

Returns a new DocumentFragment node.

The DocumentFragment() constructor must return a new DocumentFragment node whose node document is the global object's associated document.

5.7 Interface DocumentType

interface DocumentType : Node {
  readonly attribute DOMString name;
  readonly attribute DOMString publicId;
  readonly attribute DOMString systemId;
};

DocumentType nodes are simply known as doctypes.

Doctypes have an associated name, public ID, and system ID.

When a doctype is created, its name is always given. Unless explicitly given when a doctype is created, its public ID and system ID are the empty string.

The name attribute must return the name.

The publicId attribute must return the public ID.

The systemId attribute must return the system ID.

5.8 Interface Element

interface Element : Node {
  readonly attribute DOMString? namespaceURI;
  readonly attribute DOMString? prefix;
  readonly attribute DOMString localName;
  readonly attribute DOMString tagName;

           attribute DOMString id;
           attribute DOMString className;
  [SameObject] readonly attribute DOMTokenList classList;

  [SameObject] readonly attribute Attr[] attributes;
  DOMString? getAttribute(DOMString name);
  DOMString? getAttributeNS(DOMString? namespace, DOMString localName);
  void setAttribute(DOMString name, DOMString value);
  void setAttributeNS(DOMString? namespace, DOMString name, DOMString value);
  void removeAttribute(DOMString name);
  void removeAttributeNS(DOMString? namespace, DOMString localName);
  boolean hasAttribute(DOMString name);
  boolean hasAttributeNS(DOMString? namespace, DOMString localName);

  boolean matches(DOMString selectors);

  HTMLCollection getElementsByTagName(DOMString localName);
  HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
  HTMLCollection getElementsByClassName(DOMString classNames);
};

Element nodes are simply known as elements.

Elements have an associated namespace, namespace prefix, and local name. When an element is created, its local name is always given. Unless explicitly given when an element is created, its namespace and namespace prefix are null.

Elements also have an ordered attribute list. Unless explicitly given when an element is created, its attribute list is empty. An element has an attribute A if A is in its attribute list.

Applicable specifications and this specification (can) use the hooks an attribute is set, an attribute is changed, an attribute is added, and an attribute is removed, for further processing of the attribute's value.

To get an attribute for an element element using a localName and optionally a namespace, run these steps:

  1. If namespace is not given, set it to null.

  2. Return the value of the attribute in element's attribute list whose namespace is namespace and local name is localName, if it has one, and null otherwise.

To set an attribute for an element element using a localName and value, and optionally a name, prefix, and namespace, run these steps:

  1. If name is not given, set it to localName.

  2. If prefix is not given, set it to null.

  3. If namespace is not given, set it to null.

  4. Let attribute be the attribute in element's attribute list whose namespace is namespace and whose local name is localName, or null if there is no such attribute.

  5. If attribute is null, create an attribute whose local name is localName, value is value, name is name, namespace is namespace, and namespace prefix is prefix, and then append this attribute to element and terminate these steps.

  6. Change attribute from element to value.

To change an attribute attribute from an element element to value, run these steps:

  1. Queue a mutation record of "attributes" for element with name attribute's local name, namespace attribute's namespace, and oldValue attribute's value.

  2. Set attribute's value to value.

  3. An attribute is set and an attribute is changed.

To append an attribute attribute to an element element, run these steps:

  1. Queue a mutation record of "attributes" for element with name attribute's local name, namespace attribute's namespace, and oldValue null.

  2. Append the attribute to the element's attribute list.

  3. An attribute is set and an attribute is added.

To remove an attribute attribute from an element element, run these steps:

  1. Queue a mutation record of "attributes" for element with name attribute's local name, namespace attribute's namespace, and oldValue attribute's value.

  2. Remove attribute from the element's attribute list.

  3. An attribute is removed.


Elements can have an associated unique identifier (ID) and have an associated DOMTokenList object. The DOMTokenList object's associated attribute's local name is class and its associated ordered set of tokens is called the element's classes.

Historically elements could have multiple identifiers e.g. by using the HTML id attribute and a DTD. This specification makes ID a concept of the DOM and allows for only one per element, given by an id attribute.

Either when an element is created that has an id attribute whose value is not the empty string or when an element's id attribute is set to a value other than the empty string, set the element's ID to the new value.

When an element's id attribute is removed, unset the element's ID.

Either when an element is created that has a class attribute or when an element's class attribute is set, set the element's classes to the new value, parsed.

When an element's class attribute is removed, set the element's classes to the empty set.

While this specification defines user agent processing requirements for id and class attributes on any element, it makes no claims as to whether using them is conforming or not.


A node's parent of type Element is known as a parent element. If the node has a parent of a different type, its parent element is null.

The document element of a document is the element whose parent is that document, if it exists, and null otherwise.

Per the node tree constraints, there can only be one such element.

When an element or one of its ancestors is the document element, it is in a document.


namespace = element . namespaceURI

Returns the namespace.

prefix = element . prefix

Returns the namespace prefix.

localName = element . localName

Returns the local name.

qualifiedName = element . tagName

If namespace prefix is not null, returns the concatenation of namespace prefix, ":", and local name. Otherwise it returns the local name. (The return value is uppercased in an HTML document.)

The namespaceURI attribute must return the context object's namespace.

The prefix attribute must return the context object's namespace prefix.

The localName attribute must return the context object's local name.

The tagName attribute must run these steps:

  1. If context object's namespace prefix is not null, let qualified name be its namespace prefix, followed by a ":" (U+003A), followed by its local name. Otherwise, let qualified name be its local name.

  2. If the context object is in the HTML namespace and its node document is an HTML document, let qualified name be converted to ASCII uppercase.

  3. Return qualified name.


Some attributes are defined to reflect a particular content attribute. This means that on getting, these steps must be run:

  1. Get an attribute for the context object using content attribute's name and let value be the result.

  2. If value is null, return the empty string.

  3. Return value.

On setting, set an attribute for the context object using the name of the attribute and the given value.

The id attribute must reflect the "id" content attribute.

The className attribute must reflect the "class" content attribute.

The classList attribute must return the associated DOMTokenList object representing the context object's classes.


The attributes attribute must return a read only array of the context object's attribute list. The returned read only array must be live. I.e. changes to the associated attributes are reflected.

The getAttribute(name) method must run these steps:

  1. If the context object is in the HTML namespace and its node document is an HTML document, let name be converted to ASCII lowercase.

  2. Return the value of the first attribute in the context object's attribute list whose name is name, and null otherwise.

The getAttributeNS(namespace, localName) method must return the following steps:

  1. If namespace is the empty string, set it to null.

  2. Return getting an attribute for the context object using localName and namespace.

The setAttribute(name, value) method must run these steps:

  1. If name does not match the Name production in XML, throw an "InvalidCharacterError" exception.

  2. If the context object is in the HTML namespace and its node document is an HTML document, let name be converted to ASCII lowercase.

  3. Let attribute be the first attribute in the context object's attribute list whose name is name, or null if there is no such attribute.

  4. If attribute is null, create an attribute whose local name is name and value is value, and then append this attribute to the context object and terminate these steps.

  5. Change attribute from context object to value.

The setAttributeNS(namespace, name, value) method must run these steps:

  1. If namespace is the empty string, set it to null.

  2. If name does not match the Name production in XML, throw an "InvalidCharacterError" exception.

  3. If name does not match the QName production in Namespaces in XML, throw a "NamespaceError" exception.

  4. If name contains a ":" (U+003E), then split the string on it and let prefix be the part before and localName the part after. Otherwise, let prefix be null and localName be name.

  5. If prefix is not null and namespace is null, throw a "NamespaceError" exception.

  6. If prefix is "xml" and namespace is not the XML namespace, throw a "NamespaceError" exception.

  7. If name or prefix is "xmlns" and namespace is not the XMLNS namespace, throw a "NamespaceError" exception.

  8. If namespace is the XMLNS namespace and neither name nor prefix is "xmlns", throw a "NamespaceError" exception.

  9. Set an attribute for the context object using localName, value, and also name, prefix, and namespace.

The removeAttribute(name) method must run these steps:

  1. If the context object is in the HTML namespace and its node document is an HTML document, let name be converted to ASCII lowercase.

  2. Remove the first attribute from the context object whose name is name, if any.

The removeAttributeNS(namespace, localName) method must return the following steps:

  1. If namespace is the empty string, set it to null.

  2. Remove the attribute from the context object whose namespace is namespace and local name is localName, if any.

The hasAttribute(name) method must run these steps:

  1. If the context object is in the HTML namespace and its node document is an HTML document, let name be converted to ASCII lowercase.

  2. Return true if the context object has an attribute whose name is name, and false otherwise.

The hasAttributeNS(namespace, localName) method must run these steps:

  1. If namespace is the empty string, set it to null.

  2. Return true if the context object has an attribute whose namespace is namespace and local name is localName, and false otherwise.


element . matches(selectors)

Returns true if matching selectors against element's root yields element, and false otherwise.

To match a selectors string selectors against a set, run these steps:

  1. Let s be the result of parse a selector from selectors. [SELECTORS]

  2. If s is failure, throw a JavaScript TypeError.

  3. Return the result of evaluate a selector s using :scope elements set. [SELECTORS]

The matches(selectors) method must return true if the context object is in the result of running match a selectors string selectors against a set consisting of context object, and false otherwise.


The getElementsByTagName(localName) method must return the list of elements with local name localName for the context object.

The getElementsByTagNameNS(namespace, localName) method must return the list of elements with namespace namespace and local name localName for the context object.

The getElementsByClassName(classNames) method must return the list of elements with class names classNames for the context object.

5.8.1 Interface Attr

interface Attr {
  readonly attribute DOMString localName;
           attribute DOMString value;

  readonly attribute DOMString name;
  readonly attribute DOMString? namespaceURI;
  readonly attribute DOMString? prefix;

  readonly attribute boolean specified; // useless; always returns true
};

Attr objects are simply known as attributes. They are sometimes referred to as content attributes to avoid confusion with IDL attributes.

Attributes have a local name and value.

For legacy reasons, attributes also have an associated name, namespace, and namespace prefix.

When an attribute is created, its local name and value are always given. Unless explicitly given when an attribute is created, its name is identical to its local name, and its namespace and namespace prefix are null.

An A attribute is an attribute whose local name is A and whose namespace and namespace prefix are null.


The localName attribute must return the local name.

The value attribute must return the value.

Setting the value attribute must change value to the new value.


The name attribute must return the name.

The namespaceURI attribute must return the namespace.

The prefix attribute must return the namespace prefix.


The specified attribute must return true.

5.9 Interface CharacterData

interface CharacterData : Node {
  [TreatNullAs=EmptyString] attribute DOMString data;
  readonly attribute unsigned long length;
  DOMString substringData(unsigned long offset, unsigned long count);
  void appendData(DOMString data);
  void insertData(unsigned long offset, DOMString data);
  void deleteData(unsigned long offset, unsigned long count);
  void replaceData(unsigned long offset, unsigned long count, DOMString data);
};

CharacterData is an abstract interface and does not exist as node. It is used by Text, Comment, and ProcessingInstruction nodes.

Each node inheriting from the CharacterData interface has an associated mutable string called data.

To replace data of node node with offset offset, count count, and data data, run these steps:

  1. Let length be node's length attribute value.

  2. If offset is greater than length, throw an "IndexSizeError" exception.

  3. If offset plus count is greater than length let count be length minus offset.

  4. Queue a mutation record of "characterData" for node with oldValue node's data.

  5. Insert data into node's data after offset code units.

  6. Let delete offset be offset plus the number of code units in data.

  7. Starting from delete offset code units, remove count code units from node's data.

  8. For each range whose start node is node and start offset is greater than offset but less than or equal to offset plus count, set its start offset to offset.

  9. For each range whose end node is node and end offset is greater than offset but less than or equal to offset plus count, set its end offset to offset.

  10. For each range whose start node is node and start offset is greater than offset plus count, increase its start offset by the number of code units in data, then decrease it by count.

  11. For each range whose end node is node and end offset is greater than offset plus count, increase its end offset by the number of code units in data, then decrease it by count.

To substring data with node node, offset offset, and count count, run these steps:

  1. Let length be node's length attribute value.

  2. If offset is greater than length, throw an "IndexSizeError" exception.

  3. If offset plus count is greater than length, return a string whose value is the code units from the offsetth code unit to the end of node's data, and then terminate these steps.

  4. Return a string whose value is the code units from the offsetth code unit to the offset+countth code unit in node's data.

The data attribute must return data, and on setting, must replace data with node context object offset 0, count length attribute value, and data new value.

The length attribute must return the number of code units in data.

The substringData(offset, count) method must substring data with node context object, offset offset, and count count.

The appendData(data) method must replace data with node context object, offset length attribute value, count 0, and data data.

The insertData(offset, data) method must replace data with node context object, offset offset, count 0, and data data.

The deleteData(offset, count) method must replace data with node context object, offset offset, count count, and data the empty string.

The replaceData(offset, count, data) method must replace data with node context object, offset offset, count count, and data data.

5.10 Interface Text

[Constructor(optional DOMString data = "")]
interface Text : CharacterData {
  [NewObject] Text splitText(unsigned long offset);
  readonly attribute DOMString wholeText;
};
text = new Text([data = ""])

Returns a new Text node whose data is data.

text . splitText(offset)

Splits data at the given offset and returns the remainder as Text node.

text . wholeText

Returns the combined data of all direct Text node siblings.

The Text(data) constructor must return a new Text node whose data is data and node document is the global object's associated document.

To split a Text node node with offset offset, run these steps:

  1. Let length be node's length attribute value.

  2. If offset is greater than length, throw an "IndexSizeError" exception.

  3. Let count be length minus offset.

  4. Let new data be the result of substringing data with node node, offset offset, and count count.

  5. Let new node be a new Text node, with the same node document as node. Set new node's data to new data.

  6. Let parent be node's parent.

  7. If parent is not null, run these substeps:

    1. Insert new node into parent before node's next sibling.

    2. For each range whose start node is node and start offset is greater than offset, set its start node to new node and decrease its start offset by offset.

    3. For each range whose end node is node and end offset is greater than offset, set its end node to new node and decrease its end offset by offset.

    4. For each range whose start node is parent and start offset is equal to the index of node + 1, increase its start offset by one.

    5. For each range whose end node is parent and end offset is equal to the index of node + 1, increase its end offset by one.

  8. Replace data with node node, offset offset, count count, and data the empty string.

  9. If parent is null, run these substeps:

    1. For each range whose start node is node and start offset is greater than offset, set its start offset to offset.

    2. For each range whose end node is node and end offset is greater than offset, set its end offset to offset.

  10. Return new node.

The splitText(offset) method must split the context object with offset offset.

The contiguous Text nodes of a node are the node itself, the previous sibling Text node (if any) and its contiguous Text nodes, and the next sibling Text node (if any) and its contiguous Text nodes, avoiding any duplicates.

The wholeText attribute must return a concatenation of the data of the contiguous Text nodes of the context object, in tree order.

5.11 Interface ProcessingInstruction

interface ProcessingInstruction : CharacterData {
  readonly attribute DOMString target;
};

ProcessingInstruction nodes have an associated target.

The target attribute must return the target.

5.12 Interface Comment

[Constructor(optional DOMString data = "")]
interface Comment : CharacterData {
};
comment = new Comment([data = ""])

Returns a new Comment node whose data is data.

The Comment(data) constructor must return a new Comment node whose data is data and node document is the global object's associated document.

6 Ranges

6.1 Introduction to "DOM Ranges"

A Range object (range) represents a sequence of content within a node tree. Each range has a start and an end which are boundary points. A boundary point is a tuple consisting of a node and a non-negative numeric offset. So in other words, a range represents a piece of content within a node tree between two boundary points.

Ranges are frequently used in editing for selecting and copying content.

In the node tree above, a range can be used to represent the sequence “syndata is awes”. Assuming p is assigned to the p element, and em to the em element, this would be done as follows:

var range = new Range(),
    firstText = p.childNodes[1],
    secondText = em.firstChild
range.setStart(firstText, 9) // do not forget the leading space
range.setEnd(secondText, 4)
// range now stringifies to the aforementioned quote

Attributes such as src and alt in the node tree above cannot be represented by a range. The ranges concept is only useful for nodes.

Ranges are affected by mutations to the node tree. Such mutations will not invalidate a range and will try to ensure that the range still represents the same piece of content. Necessarily, a range might itself be modified as part of the mutation to the node tree when e.g. part of the content it represents is mutated.

See the insert and remove algorithms, the normalize() method, and the replace data and split algorithms for the hairy details.

6.2 Interface Range

[Constructor]
interface Range {
  readonly attribute Node startContainer;
  readonly attribute unsigned long startOffset;
  readonly attribute Node endContainer;
  readonly attribute unsigned long endOffset;
  readonly attribute boolean collapsed;
  readonly attribute Node commonAncestorContainer;

  void setStart(Node node, unsigned long offset);
  void setEnd(Node node, unsigned long offset);
  void setStartBefore(Node node);
  void setStartAfter(Node node);
  void setEndBefore(Node node);
  void setEndAfter(Node node);
  void collapse(optional boolean toStart = false);
  void selectNode(Node node);
  void selectNodeContents(Node node);

  const unsigned short START_TO_START = 0;
  const unsigned short START_TO_END = 1;
  const unsigned short END_TO_END = 2;
  const unsigned short END_TO_START = 3;
  short compareBoundaryPoints(unsigned short how, Range sourceRange);

  void deleteContents();
  [NewObject] DocumentFragment extractContents();
  [NewObject] DocumentFragment cloneContents();
  void insertNode(Node node);
  void surroundContents(Node newParent);

  [NewObject] Range cloneRange();
  void detach();

  boolean isPointInRange(Node node, unsigned long offset);
  short comparePoint(Node node, unsigned long offset);

  boolean intersectsNode(Node node);

  stringifier;
};

Range objects are simply known as ranges.

A boundary point is a (node, offset) tuple, where offset is a non-negative integer.

Generally speaking, a boundary point's offset will be between zero and the boundary point's node length, inclusive. Algorithms that modify a tree (in particular the insert, remove, replace data, and split algorithms) also modify ranges associated with that tree.

If the two nodes of boundary points (node A, offset A) and (node B, offset B) have the same root, the position of the first relative to the second is either before, equal, or after, as returned by the following algorithm:

  1. If node A is the same as node B, return equal if offset A is the same as offset B, before if offset A is less than offset B, and after if offset A is greater than offset B.

  2. If node A is following node B, compute the position of (node B, offset B) relative to (node A, offset A). If it is before, return after. If it is after, return before.

  3. If node A is an ancestor of node B:

    1. Let child equal node B.

    2. While child is not a child of node A, set child to its parent.

    3. If the index of child is less than offset A, return after.

  4. Return before.

Each range has two associated boundary points — a start and end.

For convenience, start node is start's node, start offset is start's offset, end node is end's node, and end offset is end's offset.

The root of a range is the root of its start node.

A node node is contained in a range range if node's root is the same as range's root, and (node, 0) is after range's start, and (node, length of node) is before range's end.

A node is partially contained in a range if it is an inclusive ancestor of the range's start node but not its end node, or vice versa.

Some facts to better understand these definitions:


range = new Range()

Returns a new range.

The Range() constructor must return a new range with (global object's associated document, 0) as its start and end.


node = range . startContainer

Returns range's start node.

offset = range . startOffset

Returns range's start offset.

node = range . endContainer

Returns range's end node.

offset = range . endOffset

Returns range's end offset.

collapsed = range . collapsed

Returns true if range's start and end are the same, and false otherwise.

container = range . commonAncestorContainer

Returns the node, furthest away from the document, that is an ancestor of both range's start node and end node.

The startContainer attribute must return the start node.

The startOffset attribute must return the start offset.

The endContainer attribute must return the end node.

The endOffset attribute must return the end offset.

The collapsed attribute must return true if start is the same as end, and false otherwise.

The commonAncestorContainer attribute must run these steps:

  1. Let container be start node.

  2. While container is not an inclusive ancestor of end node, let container be container's parent.

  3. Return container.


To set the start or end of a range to a boundary point (node, offset), run these steps:

  1. If node is a doctype, throw an "InvalidNodeTypeError" exception.

  2. If offset is greater than node's length, throw an "IndexSizeError" exception.

  3. Let bp be the boundary point (node, offset).

  4. If these steps were invoked as "set the start"
    1. If bp is after the range's end, or if range's root is not equal to node's root, set range's end to bp.

    2. Set range's start to bp.

    If these steps were invoked as "set the end"
    1. If bp is before the range's start, or if range's root is not equal to node's root, set range's start to bp.

    2. Set range's end to bp.

The setStart(node, offset) method must set the start of the context object to boundary point (node, offset).

The setEnd(node, offset) method must set the end of the context object to boundary point (node, offset).

The setStartBefore(node) method must run these steps:

  1. Let parent be node's parent.

  2. If parent is null, throw an "InvalidNodeTypeError" exception.

  3. Set the start of the context object to boundary point (parent, node's index).

The setStartAfter(node) method must run these steps:

  1. Let parent be node's parent.

  2. If parent is null, throw an "InvalidNodeTypeError" exception.

  3. Set the start of the context object to boundary point (parent, node's index plus one).

The setEndBefore(node) method must run these steps:

  1. Let parent be node's parent.

  2. If parent is null, throw an "InvalidNodeTypeError" exception.

  3. Set the end of the context object to boundary point (parent, node's index).

The setEndAfter(node) method must run these steps:

  1. Let parent be node's parent.

  2. If parent is null, throw an "InvalidNodeTypeError" exception.

  3. Set the end of the context object to boundary point (parent, node's index plus one).

The collapse(toStart) method must if toStart is true, set end to start, and set start to end otherwise.

To select a node node within a range range, run these steps:

  1. Let parent be node's parent.

  2. If parent is null, throw an "InvalidNodeTypeError".

  3. Let index be node's index.

  4. Set range's start to boundary point (parent, index).

  5. Set range's end to boundary point (parent, index plus one).

The selectNode(node) method must select node within context object.

The selectNodeContents(node) method must run these steps:

  1. If node is a doctype, throw an "InvalidNodeTypeError".

  2. Let length be the length of node.

  3. Set start to the boundary point (node, 0).

  4. Set end to the boundary point (node, length).


The compareBoundaryPoints(how, sourceRange) method must run these steps:

  1. If how is not one of

    throw a "NotSupportedError" exception.

  2. If context object's root is not the same as sourceRange's root, throw a "WrongDocumentError" exception.

  3. If how is:

    START_TO_START:

    Let this point be the context object's start.

    Let other point be sourceRange's start.

    START_TO_END:

    Let this point be the context object's end.

    Let other point be sourceRange's start.

    END_TO_END:

    Let this point be the context object's end.

    Let other point be sourceRange's end.

    END_TO_START:

    Let this point be the context object's start.

    Let other point be sourceRange's end.

  4. If the position of this point relative to other point is

    before
    Return −1.
    equal
    Return 0.
    after
    Return 1.

The deleteContents() method must run these steps:

  1. If start equals end, terminate these steps.

  2. Let original start node, original start offset, original end node, and original end offset be the context object's start node, start offset, end node, and end offset, respectively.

  3. If original start node and original end node are the same, and they are a Text, ProcessingInstruction, or Comment node, replace data with node original start node, offset original start offset, count original end offset minus original start offset, and data the empty string, and then terminate these steps.

  4. Let nodes to remove be a list of all the nodes that are contained in the context object, in tree order, omitting any node whose parent is also contained in the context object.

  5. If original start node is an inclusive ancestor of original end node, set new node to original start node and new offset to original start offset.

  6. Otherwise:

    1. Let reference node equal original start node.

    2. While reference node's parent is not null and is not an inclusive ancestor of original end node, set reference node to its parent.

    3. Set new node to the parent of reference node, and new offset to one plus the index of reference node.

      If reference node's parent were null, it would be the root of the context object, so would be an inclusive ancestor of original end node, and we could not reach this point.

  7. If original start node is a Text, ProcessingInstruction, or Comment node, replace data with node original start node, offset original start offset, count original start node's length minus original start offset, data the empty string.

  8. For each node in nodes to remove, in tree order, remove node from its parent.

  9. If original end node is a Text, ProcessingInstruction, or Comment node, replace data with node original end node, offset 0, count original end offset and data the empty string.

  10. Set start and end to (new node, new offset).

To extract a range range, run these steps:

  1. Let fragment be a new DocumentFragment node whose node document is range's start node's node document.

  2. If range's start equals its end, return fragment.

  3. Let original start node, original start offset, original end node, and original end offset be range's start node, start offset, end node, and end offset, respectively.

  4. If original start node equals original end node, and they are a Text, ProcessingInstruction, or Comment node:

    1. Let clone be a clone of original start node.

    2. Set the data of clone to the result of substringing data with node original start node, offset original start offset, and count original end offset minus original start offset.

    3. Append clone to fragment.

    4. Replace data with node original start node, offset original start offset, count original end offset minus original start offset, and data the empty string.

    5. Return fragment.

  5. Let common ancestor be original start node.

  6. While common ancestor is not an inclusive ancestor of original end node, set common ancestor to its own parent.

  7. Let first partially contained child be null.

  8. If original start node is not an inclusive ancestor of original end node, set first partially contained child to the first child of common ancestor that is partially contained in range.

  9. Let last partially contained child be null.

  10. If original end node is not an inclusive ancestor of original start node, set last partially contained child to the last child of common ancestor that is partially contained in range.

    These variable assignments do actually always make sense. For instance, if original start node is not an inclusive ancestor of original end node, original start node is itself partially contained in range, and so are all its ancestors up until a child of common ancestor. common ancestor cannot be original start node, because it has to be an inclusive ancestor of original end node. The other case is similar. Also, notice that the two children will never be equal if both are defined.

  11. Let contained children be a list of all children of common ancestor that are contained in range, in tree order.

  12. If any member of contained children is a doctype, throw a "HierarchyRequestError" exception.

    We do not have to worry about the first or last partially contained node, because a doctype can never be partially contained. It cannot be a boundary point of a range, and it cannot be the ancestor of anything.

  13. If original start node is an inclusive ancestor of original end node, set new node to original start node and new offset to original start offset.

  14. Otherwise:

    1. Let reference node equal original start node.

    2. While reference node's parent is not null and is not an inclusive ancestor of original end node, set reference node to its parent.

    3. Set new node to the parent of reference node, and new offset to one plus reference node's index.

      If reference node's parent is null, it would be the root of range, so would be an inclusive ancestor of original end node, and we could not reach this point.

  15. If first partially contained child is a Text, ProcessingInstruction, or Comment node:

    In this case, first partially contained child is original start node.

    1. Let clone be a clone of original start node.

    2. Set the data of clone to the result of substringing data with node original start node, offset original start offset, and count original start node's length minus original start offset.

    3. Append clone to fragment.

    4. Replace data with node original start node, offset original start offset, count original start node's length minus original start offset, and data the empty string.

  16. Otherwise, if first partially contained child is not null:

    1. Let clone be a clone of first partially contained child.

    2. Append clone to fragment.

    3. Let subrange be a new range whose start is (original start node, original start offset) and whose end is (first partially contained child, first partially contained child's length).

    4. Let subfragment be the result of extracting subrange.

    5. Append subfragment to fragment.

  17. For each contained child in contained children, append contained child to fragment.

  18. If last partially contained child is a Text, ProcessingInstruction, or Comment node:

    In this case, last partially contained child is original end node.

    1. Let clone be a clone of original end node.

    2. Set the data of clone to the result of substringing data with node original end node, offset 0, and count original end offset.

    3. Append clone to fragment.

    4. Replace data with node original end node, offset 0, count original end offset, and data the empty string.

  19. Otherwise, if last partially contained child is not null:

    1. Let clone be a clone of last partially contained child.

    2. Append clone to fragment.

    3. Let subrange be a new range whose start is (last partially contained child, 0) and whose end is (original end node, original end offset).

    4. Let subfragment be the result of extracting subrange.

    5. Append subfragment to fragment.

  20. Set range's start and end to (new node, new offset).

  21. Return fragment.

The extractContents() method must return the result of extracting context object.

To clone a range range, run these steps:

  1. Let fragment be a new DocumentFragment node whose node document is range's start node's node document.

  2. If range's start equals its end, return fragment.

  3. Let original start node, original start offset, original end node, and original end offset be range's start node, start offset, end node, and end offset, respectively.

  4. If original start node equals original end node, and they are a Text, ProcessingInstruction, or Comment node:

    1. Let clone be a clone of original start node.

    2. Set the data of clone to the result of substringing data with node original start node, offset original start offset, and count original end offset minus original start offset.

    3. Append clone to fragment.

    4. Return fragment.

  5. Let common ancestor be original start node.

  6. While common ancestor is not an inclusive ancestor of original end node, set common ancestor to its own parent.

  7. Let first partially contained child be null.

  8. If original start node is not an inclusive ancestor of original end node, set first partially contained child to the first child of common ancestor that is partially contained in range.

  9. Let last partially contained child be null.

  10. If original end node is not an inclusive ancestor of original start node, set last partially contained child to the last child of common ancestor that is partially contained in range.

    These variable assignments do actually always make sense. For instance, if original start node is not an inclusive ancestor of original end node, original start node is itself partially contained in range, and so are all its ancestors up until a child of common ancestor. common ancestor cannot be original start node, because it has to be an inclusive ancestor of original end node. The other case is similar. Also, notice that the two children will never be equal if both are defined.

  11. Let contained children be a list of all children of common ancestor that are contained in range, in tree order.

  12. If any member of contained children is a doctype, throw a "HierarchyRequestError" exception.

    We do not have to worry about the first or last partially contained node, because a doctype can never be partially contained. It cannot be a boundary point of a range, and it cannot be the ancestor of anything.

  13. If first partially contained child is a Text, ProcessingInstruction, or Comment node:

    In this case, first partially contained child is original start node.

    1. Let clone be a clone of original start node.

    2. Set the data of clone to the result of substringing data with node original start node, offset original start offset, and count original start node's length minus original start offset.

    3. Append clone to fragment.

  14. Otherwise, if first partially contained child is not null:

    1. Let clone be a clone of first partially contained child.

    2. Append clone to fragment.

    3. Let subrange be a new range whose start is (original start node, original start offset) and whose end is (first partially contained child, first partially contained child's length).

    4. Let subfragment be the result of cloning subrange.

    5. Append subfragment to fragment.

  15. For each contained child in contained children:

    1. Let clone be a clone of contained child.

    2. Append clone to fragment.

  16. If last partially contained child is a Text, ProcessingInstruction, or Comment node:

    In this case, last partially contained child is original end node.

    1. Let clone be a clone of original end node.

    2. Set the data of clone to the result of substringing data with node original end node, offset 0, and count original end offset.

    3. Append clone to fragment.

  17. Otherwise, if last partially contained child is not null:

    1. Let clone be a clone of last partially contained child.

    2. Append clone to fragment.

    3. Let subrange be a new range whose start is (last partially contained child, 0) and whose end is (original end node, original end offset).

    4. Let subfragment be the result of cloning subrange.

    5. Append subfragment to fragment.

  18. Return fragment.

The cloneContents() method must return the result of cloning context object.

To insert a node node into a range range, run these steps:

  1. If range's start node is either a ProcessingInstruction or Comment node, or a Text node whose parent is null, throw an "HierarchyRequestError" exception.

  2. If node's parent is not null, remove node from its parent.

  3. Let referenceNode be null.

  4. If range's start node is a Text node, split it with offset range's start offset, and set referenceNode to the result.

  5. Otherwise, set referenceNode to the child of start node whose index is start offset, and null if there is no such child otherwise.

  6. Let parent be range's start node if referenceNode is null, and referenceNode's parent otherwise.

  7. Let newOffset be parent's length if referenceNode is null, and referenceNode's index otherwise.

  8. Increase newOffset by node's length if node is a DocumentFragment node, and one otherwise.

  9. Pre-insert node into parent before referenceNode.

  10. If range's start and end are the same, set range's end to (parent, newOffset).

The insertNode(node) method must insert node into context object.

The surroundContents(newParent) method must run these steps:

  1. If a non-Text node is partially contained in the context object, throw an "InvalidStateError" exception.

  2. If newParent is a Document, DocumentType, or DocumentFragment node, throw an "InvalidNodeTypeError" exception.

  3. Let fragment be the result of extracting context object.

  4. If newParent has children, replace all with null within newParent.

  5. Insert newParent into context object.

  6. Append fragment to newParent.

  7. Select newParent within context object.

The cloneRange() method must return a new range with the same start and end as the context object.

The detach() method must do nothing. Its functionality (disabling a Range object) was removed, but the method itself is preserved for compatibility.


position = range . comparePoint( parent, offset )

Returns −1 if the point is before the range, 0 if the point is in the range, and 1 if the point is after the range.

intersects = range . intersectsNode( node )

Returns whether range intersects node.

The isPointInRange(node, offset) must run these steps:

  1. If node's root is different from the context object's root, return false.

  2. If node is a doctype, throw an "InvalidNodeTypeError" exception.

  3. If offset is greater than node's length, throw an "IndexSizeError" exception.

  4. If (node, offset) is before start or after end, return false.

  5. Return true.

The comparePoint(node, offset) method must run these steps:

  1. If node's root is different from the context object's root, throw a "WrongDocumentError" exception.

  2. If node is a doctype, throw an "InvalidNodeTypeError" exception.

  3. If offset is greater than node's length, throw an "IndexSizeError" exception.

  4. If (node, offset) is before start, return −1.

  5. If (node, offset) is after end, return 1.

  6. Return 0.


The intersectsNode(node) method must run these steps:

  1. If node's root is different from the context object's root, return false.

  2. Let parent be node's parent.

  3. If parent is null, return true.

  4. Let offset be node's index.

  5. If (parent, offset) is before end and (parent, offset + 1) is after start, return true.

  6. Return false.


The stringifier must run these steps:

  1. Let s be the empty string.

  2. If start node equals end node, and it is a Text node, return the substring of that Text node's data beginning at start offset and ending at end offset.

  3. If start node is a Text node, append to s the substring of that node's data from the start offset until the end.

  4. Append to s the concatenation, in tree order, of the data of all Text nodes that are contained in the context object.

  5. If end node is a Text node, append to s the substring of that node's data from its start until the end offset.

  6. Return s.


The createContextualFragment(), getClientRects(), and getBoundingClientRect() methods are defined in other specifications. [DOMPS] [CSSOMVIEW]

7 Traversal

NodeIterator and TreeWalker objects can be used to filter and traverse node trees.

Each NodeIterator and TreeWalker object has an associated active flag to avoid recursive invocations. It is initially unset.

Each NodeIterator and TreeWalker object also has an associated root node, whatToShow bitmask, and filter callback.

To filter node run these steps:

  1. If active flag is set throw an "InvalidStateError".

  2. Let n be node's nodeType attribute value minus 1.

  3. If the nth bit (where 0 is the least significant bit) of whatToShow is not set, return FILTER_SKIP.

  4. If filter is null, return FILTER_ACCEPT.

  5. Set the active flag.

  6. Let result be the return value of invoking filter.

  7. Unset the active flag.

  8. If an exception was thrown, re-throw the exception.

  9. Return result.

7.1 Interface NodeIterator

interface NodeIterator {
  [SameObject] readonly attribute Node root;
  readonly attribute Node referenceNode;
  readonly attribute boolean pointerBeforeReferenceNode;
  readonly attribute unsigned long whatToShow;
  readonly attribute NodeFilter? filter;

  Node? nextNode();
  Node? previousNode();

  void detach();
};

NodeIterator objects can be created using the createNodeIterator() method.

Each NodeIterator object has an associated iterator collection, which is a collection rooted at root, whose filter matches any node.

Before a node is removed from the iterator collection, these steps must be run:

  1. If the node is not a descendant of root and is not an ancestor of the referenceNode attribute value or the referenceNode attribute value itself, terminate these steps.

  2. If the pointerBeforeReferenceNode attribute value is false, set the referenceNode attribute to the first node preceding the node that is being removed, and terminate these steps.

  3. If the pointerBeforeReferenceNode attribute value is true and there is a node following the node that is being removed, set the referenceNode attribute to the first such node, and terminate these steps.

  4. Set the referenceNode attribute to the first node preceding the node that is being removed and set the pointerBeforeReferenceNode attribute to false.

As mentioned earlier NodeIterator objects have an associated active flag, root node, whatToShow bitmask, and filter callback as well.


The root attribute must return root.

The referenceNode and pointerBeforeReferenceNode attributes must return what they were initialized to.

The whatToShow attribute must return whatToShow.

The filter attribute must return filter.

To traverse in direction direction run these steps:

  1. Let node be the value of the referenceNode attribute.

  2. Let before node be the value of the pointerBeforeReferenceNode attribute.

  3. Run these substeps:

    1. If direction is next

      If before node is false, let node be the first node following node in the iterator collection. If there is no such node return null.

      If before node is true, set it to false.

      If direction is previous

      If before node is true, let node be the first node preceding node in the iterator collection. If there is no such node return null.

      If before node is false, set it to true.

    2. Filter node and let result be the return value.

    3. If result is FILTER_ACCEPT, go to the next step in the overall set of steps.

      Otherwise, run these substeps again.

  4. Set the referenceNode attribute to node, set the pointerBeforeReferenceNode attribute to before node, and return node.

The nextNode() method must traverse in direction next.

The previousNode() method must traverse in direction previous.

The detach() method must do nothing. Its functionality (disabling a NodeIterator object) was removed, but the method itself is preserved for compatibility.

7.2 Interface TreeWalker

interface TreeWalker {
  [SameObject] readonly attribute Node root;
  readonly attribute unsigned long whatToShow;
  readonly attribute NodeFilter? filter;
           attribute Node currentNode;

  Node? parentNode();
  Node? firstChild();
  Node? lastChild();
  Node? previousSibling();
  Node? nextSibling();
  Node? previousNode();
  Node? nextNode();
};

TreeWalker objects can be created using the createTreeWalker() method.

As mentioned earlier TreeWalker objects have an associated active flag, root node, whatToShow bitmask, and filter callback.

The root attribute must return root.

The whatToShow attribute must return whatToShow.

The filter attribute must return filter.

The currentNode attribute must return what it was initialized to.

Setting the currentNode attribute must set it to the new value.

The parentNode() method must run these steps:

  1. Let node be the value of the currentNode attribute.

  2. While node is not null and is not root, run these substeps:

    1. Let node be node's parent.

    2. If node is not null and filtering node returns FILTER_ACCEPT, then set the currentNode attribute to node, return node.

  3. Return null.

To traverse children of type type, run these steps:

  1. Let node be the value of the currentNode attribute.

  2. Set node to node's first child if type is first, and node's last child if type is last.

  3. Main: While node is not null, run these substeps:

    1. Filter node and let result be the return value.

    2. If result is FILTER_ACCEPT, then set the currentNode attribute to node and return node.

    3. If result is FILTER_SKIP, run these subsubsteps:

      1. Let child be node's first child if type is first, and node's last child if type is last.

      2. If child is not null, set node to child and goto Main.

    4. While node is not null, run these subsubsteps:

      1. Let sibling be node's next sibling if type is first, and node's previous sibling if type is last.

      2. If sibling is not null, set node to sibling and goto Main.

      3. Let parent be node's parent.

      4. If parent is null, parent is root, or parent is currentNode attribute's value, return null.

      5. Otherwise, set node to parent.

  4. Return null.

The firstChild() method must traverse children of type first.

The lastChild() method must traverse children of type last.

To traverse siblings of type type run these steps:

  1. Let node be the value of the currentNode attribute.

  2. If node is root, return null.

  3. Run these substeps:

    1. Let sibling be node's next sibling if type is next, and node's previous sibling if type is previous.

    2. While sibling is not null, run these subsubsteps:

      1. Set node to sibling.

      2. Filter node and let result be the return value.

      3. If result is FILTER_ACCEPT, then set the currentNode attribute to node and return node.

      4. Set sibling to node's first child if type is next, and node's last child if type is previous.

      5. If result is FILTER_REJECT or sibling is null, then set sibling to node's next sibling if type is next, and node's previous sibling if type is previous.

    3. Set node to its parent.

    4. If node is null or is root, return null.

    5. Filter node and if the return value is FILTER_ACCEPT, then return null.

    6. Run these substeps again.

The nextSibling() method must traverse siblings of type next.

The previousSibling() method must traverse siblings of type previous.

The previousNode() method must run these steps:

  1. Let node be the value of the currentNode attribute.

  2. While node is not root, run these substeps:

    1. Let sibling be the previous sibling of node.

    2. While sibling is not null, run these subsubsteps:

      1. Set node to sibling.

      2. Filter node and let result be the return value.

      3. While result is not FILTER_REJECT and node has a child, set node to its last child and then filter node and set result to the return value.

      4. If result is FILTER_ACCEPT, then set the currentNode attribute to node and return node.

      5. Set sibling to the previous sibling of node.

    3. If node is root or node's parent is null, return null.

    4. Set node to its parent.

    5. Filter node and if the return value is FILTER_ACCEPT, then set the currentNode attribute to node and return node.

  3. Return null.

The nextNode() method must run these steps:

  1. Let node be the value of the currentNode attribute.

  2. Let result be FILTER_ACCEPT.

  3. Run these substeps:

    1. While result is not FILTER_REJECT and node has a child, run these subsubsteps:

      1. Set node to its first child.

      2. Filter node and set result to the return value.

      3. If result is FILTER_ACCEPT, then set the currentNode attribute to node and return node.

    2. If a node is following node and is not following root, set node to the first such node.

      Otherwise, return null.

    3. Filter node and set result to the return value.

    4. If result is FILTER_ACCEPT, then set the currentNode attribute to node and return node.

    5. Run these substeps again.

7.3 Interface NodeFilter

callback interface NodeFilter {
  // Constants for acceptNode()
  const unsigned short FILTER_ACCEPT = 1;
  const unsigned short FILTER_REJECT = 2;
  const unsigned short FILTER_SKIP = 3;

  // Constants for whatToShow
  const unsigned long SHOW_ALL = 0xFFFFFFFF;
  const unsigned long SHOW_ELEMENT = 0x1;
  const unsigned long SHOW_ATTRIBUTE = 0x2; // historical
  const unsigned long SHOW_TEXT = 0x4;
  const unsigned long SHOW_CDATA_SECTION = 0x8; // historical
  const unsigned long SHOW_ENTITY_REFERENCE = 0x10; // historical
  const unsigned long SHOW_ENTITY = 0x20; // historical
  const unsigned long SHOW_PROCESSING_INSTRUCTION = 0x40;
  const unsigned long SHOW_COMMENT = 0x80;
  const unsigned long SHOW_DOCUMENT = 0x100;
  const unsigned long SHOW_DOCUMENT_TYPE = 0x200;
  const unsigned long SHOW_DOCUMENT_FRAGMENT = 0x400;
  const unsigned long SHOW_NOTATION = 0x800; // historical

  unsigned short acceptNode(Node node);
};

NodeFilter objects can be used as filter callback and provide constants for the whatToShow bitmask.

It is typically implemented as an JavaScript function.

These constants can be used as callback return value:

These constants can be used for the whatToShow bitmask:

8 Sets

Yes, the names DOMTokenList and DOMSettableTokenList are unfortunate legacy mishaps.

8.1 Interface DOMTokenList

interface DOMTokenList {
  readonly attribute unsigned long length;
  getter DOMString? item(unsigned long index);
  boolean contains(DOMString token);
  void add(DOMString... tokens);
  void remove(DOMString... tokens);
  boolean toggle(DOMString token, optional boolean force);
  stringifier;
};

A DOMTokenList object has an associated ordered set of tokens, which is initially empty.

A DOMTokenList object also has an associated element and an attribute's local name.

A DOMTokenList object's update steps are:

  1. If there is no associated attribute (when the object is a DOMSettableTokenList), terminate these steps.

  2. Set an attribute for the associated element using associated attribute's local name and the result of running the ordered set serializer for tokens.

tokenlist . length

Returns the number of tokens.

tokenlist . item(index)
tokenlist[index]

Returns the token with index index.

tokenlist . contains(token)

Returns true if token is present, and false otherwise.

Throws a "SyntaxError" exception if token is the empty string.

Throws an "InvalidCharacterError" exception if token contains any ASCII whitespace.

tokenlist . add(tokens…)

Adds all arguments passed, except those already present.

Throws a "SyntaxError" exception if one if the arguments is the empty string.

Throws an "InvalidCharacterError" exception if one of the arguments contains any ASCII whitespace.

tokenlist . remove(tokens…)

Removes arguments passed, if they are present.

Throws a "SyntaxError" exception if one if the arguments is the empty string.

Throws an "InvalidCharacterError" exception if one of the arguments contains any ASCII whitespace.

tokenlist . toggle(token [, force])

If force is not given, "toggles" token, removing it if it's present and adding it if it's not. If force is true, adds token (same as add()). If force is false, removes token (same as remove()).

Returns true if token is now present, and false otherwise.

Throws a "SyntaxError" exception if token is empty.

Throws an "InvalidCharacterError" exception if token contains any spaces.

The length attribute must return the number of tokens in the tokens.

The object's supported property indices are the numbers in the range zero to the number of tokens in tokens minus one, unless tokens is empty, in which case there are no supported property indices.

The item(index) method must run these steps:

  1. If index is equal to or greater than the number of tokens in tokens, return null.

  2. Return the indexth token in tokens.

The contains(token) method must run these steps:

  1. If token is the empty string, then throw a "SyntaxError" exception.

  2. If token contains any ASCII whitespace, then throw an "InvalidCharacterError" exception.

  3. Return true if token is in tokens, and false otherwise.

The add(tokens…) method must run these steps:

  1. If one of tokens is the empty string, throw a "SyntaxError" exception.

  2. If one of tokens contains any ASCII whitespace, then throw an "InvalidCharacterError" exception.

  3. For each token in tokens, in given order, that is not in tokens, append token to tokens.

  4. Run the update steps.

The remove(tokens…) method must run these steps:

  1. If one of tokens is the empty string, throw a "SyntaxError" exception.

  2. If one of tokens contains any ASCII whitespace, then throw an "InvalidCharacterError" exception.

  3. For each token in tokens, remove token from tokens.

  4. Run the update steps.

The toggle(token, force) method must run these steps:

  1. If token is the empty string, throw a "SyntaxError" exception.

  2. If token contains any ASCII whitespace, throw an "InvalidCharacterError" exception.

  3. If token is in tokens, run these substeps:

    1. If force is either not passed or is false, then remove token from tokens, run the update steps, and return false.

    2. Otherwise, return true.

  4. Otherwise, run these substeps:

    1. If force is passed and is false, return false.

    2. Otherwise, append token to tokens, run the update steps, and return true.

The stringifier must return the result of the ordered set serializer for tokens.

8.2 Interface DOMSettableTokenList

interface DOMSettableTokenList : DOMTokenList {
            attribute DOMString value;
};

A DOMSettableTokenList object is equivalent to a DOMTokenList object without an associated attribute.

tokenlist . value

Returns the associated set as string.

Can be set, to change the associated set via a string.

The value attribute must return the result of the ordered set serializer for tokens.

Setting the value attribute must run the ordered set parser for the given value and set tokens to the result.

9 Historical

As explained in goals this specification is a significant revision of various DOM specifications. This section attempts to enumerate the changes.

9.1 DOM Events

These are the changes made to the features described in the "DOM Event Architecture", "Basic Event Interfaces", "Mutation Events", and "Mutation Name Event Types" chapters of DOM Level 3 Events. The other chapters are defined by the UI Events specification. [DOM3EVENTS] [UIEVENTS]

9.2 DOM Core

These are the changes made to the features described in DOM Level 3 Core.

DOMString and DOMTimeStamp are now defined in Web IDL.

Node now inherits from EventTarget.

Nodes are implicitly adopted across document boundaries.

Doctypes now always have a node document and can be moved across document boundaries.

ProcessingInstruction now inherits from CharacterData.

DOMError is completely redesigned.

The remainder of interfaces and interface members listed in this section were removed to simplify the DOM platform. Implementations conforming to this specification will not support them.

It is not yet clear if it would be web-compatible to remove all the following features. The editors welcome any data showing that some of these features should be reintroduced.

Interfaces:

Interface members:

Node
Document
DOMImplementation
Attr

No longer inherits from Node and therefore completely changed.

Element
DocumentType
Text

9.3 DOM Ranges

These are the changes made to the features described in the "Document Object Model Range" chapter of DOM Level 2 Traversal and Range.

9.4 DOM Traversal

These are the changes made to the features described in the "Document Object Model Traversal" chapter of DOM Level 2 Traversal and Range.

References

[CSSOMVIEW]
(Non-normative)
[DOM2TR]
(Non-normative) Document Object Model (DOM) Level 2 Traversal and Range Specification, Joe Kesselman, Jonathan Robie, Mike Champion et al.. W3C.
[DOM3CORE]
(Non-normative) Document Object Model (DOM) Level 3 Core Specification, Arnaud Le Hors, Philippe Le Hégaret, Lauren Wood et al.. W3C.
[DOM3EVENTS]
(Non-normative) Document Object Model (DOM) Level 3 Events Specification, Travis Leithead. W3C.
[DOMPS]
(Non-normative) DOM Parsing and Serialization, T. Leithead. Work in Progress. W3C.
[ELEMENTTRAVERSAL]
(Non-normative) Element Traversal Specification, Doug Schepers. W3C.
[ENCODING]
Encoding, A. van Kesteren, J. Bell, A. Phillips. W3C.
[HTML]
HTML5, R. Berjon, T. Leithead, E. Doyle Navara, E. O'Connor, S. Pfeiffer. W3C.
[ORIGIN]
The Web Origin Concept, Adam Barth. IETF.
[RFC2119]
Key words for use in RFCs to Indicate Requirement Levels, Scott Bradner. IETF.
[SELECTORS]
Selectors, E. Etemad, T. Atkins. W3C.
[SELECTORSAPI]
(Non-normative) Selectors API Level 2, Lachlan Hunt. W3C.
[UIEVENTS]
UI Events, Gary Kacmarcik and Travis Leithead. W3C.
[URL]
  • URL, Anne van Kesteren. WHATWG.
  • RFC3986, T. Berners-Lee; R. Fielding; L. Masinter. IETF.
[WEBIDL]
Web IDL, Cameron McCormack. W3C.
[XML]
Extensible Markup Language, Tim Bray, Jean Paoli, C. M. Sperberg-McQueen et al.. W3C.
[XMLNS]
Namespaces in XML, Tim Bray, Dave Hollander, Andrew Layman et al.. W3C.

Acknowledgments

Thanks to Adam Klein, Adrian Bateman, Alex Russell, Arkadiusz Michalski, Arun Ranganathan, Jake Archibald, Boris Zbarsky, Brandon Slade, Brandon Wallace, Brian Kardell, Cameron McCormack, Christophe Dumez, Daniel Glazman, David Bruant, David Flanagan, David Håsäther, Dethe Elza, Dimitri Glazkov, Domenic Denicola, Dominic Cooney, Dominique Hazaël-Massieux, Erik Arvidsson, Glenn Maynard, Harald Alvestrand, Henri Sivonen, Igor Bukanov, Jacob Rossi, Jake Verbaten, James Graham, James Robinson, Jens Lindström, João Eiras, Jonas Sicking, Joshua Bell, Justin Summerlin, 呂康豪 (Kang-Hao Lu), Kevin Sweeney, Manish Goregaokar, Manish Tripathi, Marcos Caceres, Mark Miller, Mats Palmgren, Mounir Lamouri, Michael™ Smith, Ojan Vafai, Olli Pettay, Ondřej Žára, Philip Jägenstedt, Rafael Weinstein, Rick Waldron, Robbert Broersma, Robin Berjon, Rune F. Halvorsen, Ryosuke Niwa, Seo Sanghyeon, Shiki Okasaka, Stig Halvorsen, Tab Atkins, Timo Tijhof, Travis Leithead, Yehuda Katz, and Zack Weinberg for their useful comments.

Special thanks to Geoffrey Sneddon and Simon Pieters for first specifying the Nodes section of this specification and their useful comments.

Special thanks also to Ian Hickson for first specifying some parts of this specification in HTML and his useful comments. [HTML]

Finally, while this specification has been written from scratch, special thanks should also be extended to the editors of the various specifications that previously defined the features in this specification: Arnaud Le Hors, Björn Höhrmann, Doug Schepers, Gavin Nicol, Joe Kesselman, Jonathan Robie, Lachlan Hunt, Lauren Wood, Mike Champion, Peter Sharpe, Philippe Le Hégaret, Robin Berjon, Steve Byrne, Tom Pixley, and Vidur Apparao.