--- title: Node slug: Web/API/Node tags: - API - DOM - DOM Reference - Interface - NeedsTranslation - Node - Reference - TopicStub translation_of: Web/API/Node ---
{{APIRef("DOM")}}

Node 是一個被多種 DOM 類型繼承的介面，它讓各種類型的 DOM 都能以同樣的方式來操作。如繼承了相同的方法，或能以相同的方式測試。

Node 繼承自 {{domxref("EventTarget")}}，而繼承了 Node 的屬性及方法的介面則有：{{domxref("Document")}}、{{domxref("Element")}}、{{domxref("CharacterData")}}（被 {{domxref("Text")}}、{{domxref("Comment")}} 以及 {{domxref("CDATASection")}} 所繼承）、{{domxref("ProcessingInstruction")}}、{{domxref("DocumentFragment")}}、{{domxref("DocumentType")}}、{{domxref("Notation")}}、{{domxref("Entity")}}、{{domxref("EntityReference")}}。

These interfaces may return null in particular cases where the methods and properties are not relevant. They may throw an exception - for example when adding children to a node type for which no children can exist.

{{InheritanceDiagram}}

屬性

Inherits properties from its parents {{domxref("EventTarget")}}.[1]

{{domxref("Node.baseURI")}} {{readonlyInline}}
Returns a {{domxref("DOMString")}} representing the base URL. The concept of base URL changes from one language to another; in HTML, it corresponds to the protocol, the domain name and the directory structure, that is all until the last '/'.
{{domxref("Node.baseURIObject")}} {{Non-standard_inline()}}
(Not available to web content.) The read-only {{ Interface("nsIURI") }} object representing the base URI for the element.
{{domxref("Node.childNodes")}} {{readonlyInline}}
Returns a live {{domxref("NodeList")}} containing all the children of this node. {{domxref("NodeList")}} being live means that if the children of the Node change, the {{domxref("NodeList")}} object is automatically updated.
{{domxref("Node.firstChild")}} {{readonlyInline}}
Returns a {{domxref("Node")}} representing the first direct child node of the node, or null if the node has no child.
{{domxref("Node.lastChild")}} {{readonlyInline}}
Returns a {{domxref("Node")}} representing the last direct child node of the node, or null if the node has no child.
{{domxref("Node.nextSibling")}} {{readonlyInline}}
Returns a {{domxref("Node")}} representing the next node in the tree, or null if there isn't such node.
{{domxref("Node.nodeName")}} {{readonlyInline}}
Returns a {{domxref("DOMString")}} containing the name of the Node. The structure of the name will differ with the node type. E.g. An {{domxref("HTMLElement")}} will contain the name of the corresponding tag, like 'audio' for an {{domxref("HTMLAudioElement")}}, a {{domxref("Text")}} node will have the '#text' string, or a {{domxref("Document")}} node will have the '#document' string.
{{domxref("Node.nodePrincipal")}} {{Non-standard_inline()}}
A {{ Interface("nsIPrincipal") }} representing the node principal.
{{domxref("Node.nodeType")}}{{readonlyInline}}
Returns an unsigned short representing the type of the node. Possible values are:
Name Value
ELEMENT_NODE 1
ATTRIBUTE_NODE {{deprecated_inline()}} 2
TEXT_NODE 3
CDATA_SECTION_NODE {{deprecated_inline()}} 4
ENTITY_REFERENCE_NODE {{deprecated_inline()}} 5
ENTITY_NODE {{deprecated_inline()}} 6
PROCESSING_INSTRUCTION_NODE 7
COMMENT_NODE 8
DOCUMENT_NODE 9
DOCUMENT_TYPE_NODE 10
DOCUMENT_FRAGMENT_NODE 11
NOTATION_NODE {{deprecated_inline()}} 12
{{domxref("Node.nodeValue")}}
Returns / Sets the value of the current node
{{domxref("Node.ownerDocument")}} {{readonlyInline}}
Returns the {{domxref("Document")}} that this node belongs to. If no document is associated with it, returns null.
{{domxref("Node.parentNode")}} {{readonlyInline}}
Returns a {{domxref("Node")}} that is the parent of this node. If there is no such node, like if this node is the top of the tree or if doesn't participate in a tree, this property returns null.
{{domxref("Node.parentElement")}} {{readonlyInline}}
Returns an {{domxref("Element")}} that is the parent of this node. If the node has no parent, or if that parent is not an {{domxref("Element")}}, this property returns null.
{{domxref("Node.previousSibling")}} {{readonlyInline}}
Returns a {{domxref("Node")}} representing the previous node in the tree, or null if there isn't such node.
{{domxref("Node.textContent")}}
Returns / Sets the textual content of an element and all its descendants.

Deprecated properties

{{domxref("Node.rootNode")}} {{readOnlyInline}} {{deprecated_inline}}
Returns a {{domxref("Node")}} object representing the topmost node in the tree, or the current node if it's the topmost node in the tree. This has been replaced by {{domxref("Node.getRootNode()")}}.

Obsolete properties

{{domxref("Node.localName")}} {{obsolete_inline}}{{readonlyInline}}
Returns a {{domxref("DOMString")}} representing the local part of the qualified name of an element.

Note: In Firefox 3.5 and earlier, the property upper-cases the local name for HTML elements (but not XHTML elements). In later versions, this does not happen, so the property is in lower case for both HTML and XHTML. {{gecko_minversion_inline("1.9.2")}}

{{domxref("Node.namespaceURI")}} {{obsolete_inline}}{{readonlyInline}}
The namespace URI of this node, or null if it is no namespace.

Note: In Firefox 3.5 and earlier, HTML elements are in no namespace. In later versions, HTML elements are in the https://www.w3.org/1999/xhtml/ namespace in both HTML and XML trees. {{gecko_minversion_inline("1.9.2")}}

{{domxref("Node.prefix")}} {{obsolete_inline}}{{readonlyInline}}
Is a {{domxref("DOMString")}} representing the namespace prefix of the node, or null if no prefix is specified.

方法

Inherits methods from its parent, {{domxref("EventTarget")}}.[1]

{{domxref("Node.appendChild()")}}
Adds the specified childNode argument as the last child to the current node.
If the argument referenced an existing node on the DOM tree, the node will be detached from its current position and attached at the new position.
{{domxref("Node.cloneNode()")}}
Clone a {{domxref("Node")}}, and optionally, all of its contents. By default, it clones the content of the node.
{{domxref("Node.compareDocumentPosition()")}}
Compares the position of the current node against another node in any other document.
{{domxref("Node.contains()")}}
Returns a {{jsxref("Boolean")}} value indicating whether a node is a descendant of a given node or not.
{{domxref("Node.getRootNode()")}}
Returns the context object's root which optionally includes the shadow root if it is available.
{{domxref("Node.hasChildNodes()")}}
Returns a {{jsxref("Boolean")}} indicating if the element has any child nodes, or not.
{{domxref("Node.insertBefore()")}}
Inserts a {{domxref("Node")}} before the reference node as a child of the current node.
{{domxref("Node.isDefaultNamespace()")}}
Accepts a namespace URI as an argument and returns a {{jsxref("Boolean")}} with a value of true if the namespace is the default namespace on the given node or false if not.
{{domxref("Node.isEqualNode()")}}
Returns a {{jsxref("Boolean")}} which indicates whether or not two nodes are of the same type and all their defining data points match.
{{domxref("Node.isSameNode()")}}
Returns a {{jsxref("Boolean")}} value indicating whether or not the two nodes are the same (that is, they reference the same object).
{{domxref("Node.lookupPrefix()")}}
Returns a {{domxref("DOMString")}} containing the prefix for a given namespace URI, if present, and null if not. When multiple prefixes are possible, the result is implementation-dependent.
{{domxref("Node.lookupNamespaceURI()")}}
Accepts a prefix and returns the namespace URI associated with it on the given node if found (and null if not). Supplying null for the prefix will return the default namespace.
{{domxref("Node.normalize()")}}
Clean up all the text nodes under this element (merge adjacent, remove empty).
{{domxref("Node.removeChild()")}}
Removes a child node from the current element, which must be a child of the current node.
{{domxref("Node.replaceChild()")}}
Replaces one child {{domxref("Node")}} of the current one with the second one given in parameter.

Obsolete methods

{{domxref("Node.getFeature()")}} {{obsolete_inline}}
x
{{domxref("Node.getUserData()")}} {{obsolete_inline}}
Allows a user to get some {{domxref("DOMUserData")}} from the node.
{{domxref("Node.hasAttributes()")}} {{obsolete_inline}}
Returns a {{jsxref("Boolean")}} indicating if the element has any attributes, or not.
{{domxref("Node.isSupported()")}} {{obsolete_inline}}
Returns a {{jsxref("Boolean")}} flag containing the result of a test whether the DOM implementation implements a specific feature and this feature is supported by the specific node.
{{domxref("Node.setUserData()")}} {{obsolete_inline}}
Allows a user to attach, or remove, {{domxref("DOMUserData")}} to the node.

範例

Browse all child nodes

The following function recursively cycles all child nodes of a node and executes a callback function upon them (and upon the parent node itself).

function DOMComb (oParent, oCallback) {
  if (oParent.hasChildNodes()) {
    for (var oNode = oParent.firstChild; oNode; oNode = oNode.nextSibling) {
      DOMComb(oNode, oCallback);
    }
  }
  oCallback.call(oParent);
}

Syntax

DOMComb(parentNode, callbackFunction);

Description

Recursively cycle all child nodes of parentNode and parentNode itself and execute the callbackFunction upon them as this objects.

Parameters

parentNode
The parent node (Node Object).
callbackFunction
The callback function (Function).

Sample usage

The following example send to the console.log the text content of the body:

function printContent () {
  if (this.nodeValue) { console.log(this.nodeValue); }
}

onload = function () {
  DOMComb(document.body, printContent);
};

Remove all children nested within a node

Element.prototype.removeAll = function () {
  while (this.firstChild) { this.removeChild(this.firstChild); }
  return this;
};

Sample usage

/* ... an alternative to document.body.innerHTML = "" ... */
document.body.removeAll();

規範

Specification Status Comment
{{SpecName('DOM WHATWG', '#interface-node', 'Node')}} {{Spec2('DOM WHATWG')}} Removed the following properties: attributes, namespaceURI, prefix, and localName.
Removed the following methods: isSupported(), hasAttributes(), getFeature(), setUserData(), and getUserData().
{{SpecName('DOM3 Core', 'core.html#ID-1950641247', 'Node')}} {{Spec2('DOM3 Core')}} The methods insertBefore(), replaceChild(), removeChild(), and appendChild() returns one more kind of error (NOT_SUPPORTED_ERR) if called on a {{domxref("Document")}}.
The normalize() method has been modified so that {{domxref("Text")}} node can also be normalized if the proper {{domxref("DOMConfiguration")}} flag is set.
Added the following methods: compareDocumentPosition(), isSameNode(), lookupPrefix(), isDefaultNamespace(), lookupNamespaceURI(), isEqualNode(), getFeature(), setUserData(), and getUserData().
Added the following properties: baseURI and textContent.
{{SpecName('DOM2 Core', 'core.html#ID-1950641247', 'Node')}} {{Spec2('DOM2 Core')}} The ownerDocument property was slightly modified so that {{domxref("DocumentFragment")}} also returns null.
Added the following properties: namespaceURI, prefix, and localName.
Added the following methods: normalize(), isSupported() and hasAttributes().
{{SpecName('DOM1', 'level-one-core.html#ID-1950641247', 'Node')}} {{Spec2('DOM1')}} Initial definition

瀏覽器相容性

{{CompatibilityTable}}

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support {{CompatVersionUnknown}}[1] {{CompatVersionUnknown}} {{CompatGeckoDesktop("1.0")}} {{CompatVersionUnknown}} {{CompatVersionUnknown}}[1] {{CompatVersionUnknown}}[1]
getFeature(){{obsolete_inline}} {{CompatNo}} {{CompatUnknown}} {{CompatGeckoDesktop("1.0")}}
{{CompatNo}}{{CompatGeckoDesktop("7.0")}}		 {{CompatUnknown}} {{CompatNo}} {{CompatNo}}
getUserData(), setUserData() and hasAttributes() {{deprecated_inline}} {{CompatNo}} {{CompatUnknown}} {{CompatGeckoDesktop("1.0")}}
{{CompatNo}}{{CompatGeckoDesktop("22.0")}}		 {{CompatUnknown}} {{CompatNo}} {{CompatNo}}
isSameNode() {{CompatVersionUnknown}} {{CompatUnknown}} {{CompatGeckoDesktop("1.0")}}
Removed in {{CompatGeckoDesktop("10")}}
Returned in {{CompatGeckoDesktop("48")}}		 {{CompatUnknown}} {{CompatNo}} {{CompatNo}}
isSupported() {{obsolete_inline}} {{CompatNo}} {{CompatUnknown}} {{CompatGeckoDesktop("1.0")}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}}
attributes {{CompatNo}} {{CompatUnknown}} {{CompatGeckoDesktop("1.0")}}
{{CompatNo}}{{CompatGeckoDesktop("22.0")}}[2]		 {{CompatNo}} {{CompatNo}} {{CompatNo}}
rootNode() {{CompatUnknown}} {{CompatUnknown}} CompatGeckoDesktop(48)}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}}
namespaceURI, localName, prefix {{obsolete_inline}} {{CompatVersionUnknown}}
{{CompatNo}}46.0[3]		 {{CompatUnknown}} {{CompatVersionUnknown}}
{{CompatNo}}48.0[3]		 {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}}
getRootNode(), and rootNode deprecated {{CompatChrome(54.0)}} {{CompatUnknown}} {{CompatGeckoDesktop(53)}} {{CompatUnknown}} {{CompatOpera(41)}} {{CompatUnknown}}
Feature Android Android Webview Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support {{CompatUnknown}} {{CompatVersionUnknown}}[1] {{CompatVersionUnknown}} {{CompatGeckoMobile("1.0")}} {{CompatVersionUnknown}} {{CompatVersionUnknown}}[1] {{CompatVersionUnknown}}[1] {{CompatVersionUnknown}}[1]
getFeature(){{obsolete_inline}} {{CompatNo}} {{CompatNo}} {{CompatUnknown}} {{CompatGeckoMobile("1.0")}}
{{CompatNo}}{{CompatGeckoDesktop("7.0")}}		 {{CompatUnknown}} {{CompatNo}} {{CompatNo}} {{CompatNo}}
getUserData(), setUserData() and hasAttributes() {{deprecated_inline}} {{CompatNo}} {{CompatNo}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatNo}}
isSameNode() {{CompatUnknown}} {{CompatVersionUnknown}} {{CompatUnknown}}

{{CompatGeckoDesktop("1.0")}}
Removed in {{CompatGeckoDesktop("10")}}
Returned in {{CompatGeckoDesktop("48")}}

 {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatVersionUnknown}}
isSupported() {{obsolete_inline}} {{CompatUnknown}} {{CompatNo}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatNo}}
attributes {{CompatUnknown}} {{CompatNo}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatNo}}
rootNode() {{CompatUnknown}} {{CompatNo}} {{CompatUnknown}} {{CompatGeckoMobile(48)}} {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatNo}}
namespaceURI, localName, prefix {{obsolete_inline}} {{CompatUnknown}} {{CompatNo}} {{CompatUnknown}} {{CompatVersionUnknown}}
{{CompatNo}}48.0[3]		 {{CompatUnknown}} {{CompatUnknown}} {{CompatUnknown}} {{CompatNo}}
getRootNode(), and rootNode deprecated {{CompatNo}} {{CompatChrome(54.0)}} {{CompatUnknown}} {{CompatGeckoMobile(53)}} {{CompatUnknown}} {{CompatOperaMobile(41)}} {{CompatUnknown}} {{CompatChrome(54.0)}}

[1] WebKit and old versions of Blink incorrectly do not make Node inherit from {{domxref("EventTarget")}}.

[2] In Gecko 22.0 {{geckoRelease("22.0")}} the attributes property was moved to {{domxref("Element")}}.

[3] The properties were moved to the {{domxref("Element")}} and {{domxref("Attr")}} APIs according to the DOM4 standard.