Document.createTreeWalker()
The Document.createTreeWalker()
creator method returns a
newly created TreeWalker
object.
Syntax
document.createTreeWalker(root[, whatToShow[, filter[, expandEntityReferences]]]);
Parameters
root
-
A root
Node
of thisTreeWalker
traversal. Typically this will be an element owned by the document. whatToShow
Optional-
A
unsigned long
representing a bitmask created by combining the constant properties ofNodeFilter
. It is a convenient way of filtering for certain types of node. It defaults to0xFFFFFFFF
representing theSHOW_ALL
constant.Constant Numerical value Description NodeFilter.SHOW_ALL
4294967295
(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
Legacy, no longer usable. NodeFilter.SHOW_ENTITY_REFERENCE
16
Legacy, no longer usable. NodeFilter.SHOW_NOTATION
2048
Legacy, no longer usable. NodeFilter.SHOW_PROCESSING_INSTRUCTION
64
Shows ProcessingInstruction
nodes.NodeFilter.SHOW_TEXT
4
Shows Text
nodes. filter
Optional-
A
NodeFilter
, that is an object with a methodacceptNode
, which is called by theTreeWalker
to determine whether or not to accept a node that has passed thewhatToShow
check. expandEntityReferences
Optional-
A boolean flag indicating if when discarding an entity reference its whole sub-tree must be discarded at the same time.
Return value
A new TreeWalker
object.
Example
The following example goes through all nodes in the body,
filters out any non nodes that aren't elements (with the `NodeFilter.SHOW_ELEMENT` value),
marks each remaining node as acceptable (The acceptNode()
method could make
a different decision.), and then makes use of tree walker iterator
that is created to advance through the nodes (now all elements) and push them into an
array.
var treeWalker = document.createTreeWalker(
document.body,
NodeFilter.SHOW_ELEMENT,
{ acceptNode: function(node) { return NodeFilter.FILTER_ACCEPT; } },
false
);
var nodeList = [];
var currentNode = treeWalker.currentNode;
while(currentNode) {
nodeList.push(currentNode);
currentNode = treeWalker.nextNode();
}
Specifications
Specification |
---|
DOM Standard # dom-document-createtreewalker |
Browser compatibility
BCD tables only load in the browser
See also
- The interface of the object it creates:
TreeWalker
.