Web/API/TreeWalker

From Get docs


The TreeWalker object represents the nodes of a document subtree and a position within them.

A TreeWalker can be created using the Document.createTreeWalker() method.

Properties

This interface doesn't inherit any property.

TreeWalker.root Read only
Returns a Node representing the root node as specified when the TreeWalker was created.
TreeWalker.whatToShow Read only
Returns an unsigned long being a bitmask made of constants describing the types of Node that must be presented. Non-matching nodes are skipped, but their children may be included, if relevant. The possible values are:
Constant Numerical value Description
NodeFilter.SHOW_ALL -1 (that is the max value of unsigned long) Shows all nodes.
NodeFilter.SHOW_ATTRIBUTE ' 2 Shows attribute Attr nodes. This is meaningful only when creating a TreeWalker with an Attr node as its root. In this case, it means that the attribute node will appear in the first position of the iteration or traversal. Since attributes are never children of other nodes, they do not appear when traversing over the document tree.
NodeFilter.SHOW_CDATA_SECTION ' 8 Shows CDATASection nodes.
NodeFilter.SHOW_COMMENT 128 Shows Comment nodes.
NodeFilter.SHOW_DOCUMENT 256 Shows Document nodes.
NodeFilter.SHOW_DOCUMENT_FRAGMENT 1024 Shows DocumentFragment nodes.
NodeFilter.SHOW_DOCUMENT_TYPE 512 Shows DocumentType nodes.
NodeFilter.SHOW_ELEMENT 1 Shows Element nodes.
NodeFilter.SHOW_ENTITY ' 32 Shows Entity nodes. This is meaningful only when creating a TreeWalker with an Entity node as its root; in this case, it means that the Entity node will appear in the first position of the traversal. Since entities are not part of the document tree, they do not appear when traversing over the document tree.
NodeFilter.SHOW_ENTITY_REFERENCE ' 16 Shows EntityReference nodes.
NodeFilter.SHOW_NOTATION ' 2048 Shows Notation nodes. This is meaningful only when creating a TreeWalker with a Notation node as its root; in this case, it means that the Notation node will appear in the first position of the traversal. Since entities are not part of the document tree, they do not appear when traversing over the document tree.
NodeFilter.SHOW_PROCESSING_INSTRUCTION 64 Shows ProcessingInstruction nodes.
NodeFilter.SHOW_TEXT 4 Shows Text nodes.
TreeWalker.filter Read only
Returns a NodeFilter used to select the relevant nodes.
TreeWalker.expandEntityReferences Read only '
Is a Boolean indicating, when discarding an EntityReference its whole sub-tree must be discarded at the same time.
TreeWalker.currentNode
Is the Node on which the TreeWalker is currently pointing at.

Methods

This interface doesn't inherit any method.

Note: in the context of a TreeWalker, a node is visible if it exists in the logical view determined by the whatToShow and filter parameter arguments. (Whether or not the node is visible on the screen is irrelevant.)


TreeWalker.parentNode()
Moves the current Node to the first visible ancestor node in the document order, and returns the found node. It also moves the current node to this one. If no such node exists, or if it is before that the root node defined at the object construction, returns null and the current node is not changed.
TreeWalker.firstChild()
Moves the current Node to the first visible child of the current node, and returns the found child. It also moves the current node to this child. If no such child exists, returns null and the current node is not changed.
TreeWalker.lastChild()
Moves the current Node to the last visible child of the current node, and returns the found child. It also moves the current node to this child. If no such child exists, null is returned and the current node is not changed.
TreeWalker.previousSibling()
Moves the current Node to its previous sibling, if any, and returns the found sibling. If there is no such node, return null and the current node is not changed.
TreeWalker.nextSibling()
Moves the current Node to its next sibling, if any, and returns the found sibling. If there is no such node, null is returned and the current node is not changed.
TreeWalker.previousNode()
Moves the current Node to the previous visible node in the document order, and returns the found node. It also moves the current node to this one. If no such node exists, or if it is before that the root node defined at the object construction, returns null and the current node is not changed.
TreeWalker.nextNode()
Moves the current Node to the next visible node in the document order, and returns the found node. It also moves the current node to this one. If no such node exists, returns null and the current node is not changed.

Specifications

Specification Status Comment
DOMThe definition of 'TreeWalker' in that specification. Living Standard Removed the expandEntityReferences property.
Document Object Model (DOM) Level 2 Traversal and Range SpecificationThe definition of 'TreeWalker' in that specification. Obsolete Initial definition.

Browser compatibility

Update compatibility data on GitHub

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
TreeWalker Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

currentNode Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

expandEntityReferences

Deprecated'

Chrome

Full support 1

Edge

Full support 12

Firefox

No support 4 — 21

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

No support 4 — 21

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

filter Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

firstChild Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

lastChild Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

nextNode Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

nextSibling Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

parentNode Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

previousNode Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

previousSibling Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

root Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

whatToShow Chrome

Full support 1

Edge

Full support 12

Firefox

Full support 4

IE

Full support 9

Opera

Full support 9

Safari

Full support 3

WebView Android

Full support 3

Chrome Android

Full support Yes

Firefox Android

Full support 4

Opera Android

Full support 10.1

Safari iOS

Full support 3

Samsung Internet Android

Full support Yes

Legend

Full support  
Full support
No support  
No support
Deprecated. Not for use in new websites.'
Deprecated. Not for use in new websites.


See also