TreeWalker

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 to 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 if, 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.

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, returns null 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, return null 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
DOM
The definition of 'TreeWalker' in that specification.
Living Standard Removed the expandEntityReferences property.
Document Object Model (DOM) Level 2 Traversal and Range Specification
The definition of 'TreeWalker' in that specification.
Recommendation Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 1.0 2.0 (1.8.1) 9.0 9.0 3.0
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) 1.0 (1.8.1) (Yes) 9.0 3.0

See also

Document Tags and Contributors

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Contributors to this page: teoli, MHasan, treycordova, ethertank, Sheppy, Hopson, SylvainPasche
Last updated by: teoli,