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 theTreeWalker
was created. TreeWalker.whatToShow
Read only- Returns an
unsigned long
being a bitmask made of constants describing the types ofNode
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 ofunsigned long
)Shows all nodes. NodeFilter.SHOW_ATTRIBUTE
2
Shows attribute Attr
nodes. This is meaningful only when creating aTreeWalker
with anAttr
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 aTreeWalker
with anEntity
node as its root; in this case, it means that theEntity
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 aTreeWalker
with aNotation
node as its root; in this case, it means that theNotation
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 anEntityReference
its whole sub-tree must be discarded at the same time. TreeWalker.currentNode
- Is the
Node
on which theTreeWalker
is currently pointing at.
Methods
This interface doesn't inherit any method.
Note that the TreeWalker only considers visible DOM nodes.
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, returnsnull
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, returnsnull
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, returnsnull
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, returnnull
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, returnnull
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, returnsnull
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, returnsnull
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
- The creator method:
Document.createTreeWalker()
. - Related interfaces:
NodeFilter
,NodeIterator
.
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/treewalker