Document.createTreeWalker()
Вызов метода Document.createTreeWalker()
возвращает новый объект класса TreeWalker
.
Синтаксис
document.createTreeWalker(root, whatToShow[, filter[, entityReferenceExpansion]]);
Параметры
root
-
корневой узел
Node
дляTreeWalker
. Чаще всего это элемент принадлежащий document. whatToShow
Необязательный-
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.Константа Числовое значение Описание NodeFilter.SHOW_ALL
-1
(that is the max value ofunsigned long
)Показывать все узлы. NodeFilter.SHOW_ATTRIBUTE
Устарело2
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
Устарело8
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
Устарело32
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
Устарело16
Shows EntityReference
nodes.NodeFilter.SHOW_NOTATION
Устарело2048
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. filter
Необязательный-
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. entityReferenceExpansion
Необязательный-
A
Boolean
flag indicating if when discarding anEntityReference
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, reduces the set of nodes to elements, simply passes through as acceptable each node (it could reduce the set in the acceptNode()
method instead), 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 = [];
while (treeWalker.nextNode()) nodeList.push(treeWalker.currentNode);
Спецификации
Specification |
---|
DOM Standard # dom-document-createtreewalker |
Совместимость с браузерами
BCD tables only load in the browser
Смотрите также
- The interface of the object it creates:
TreeWalker
.