Document.createTreeWalker()

Вызов метода Document.createTreeWalker() возвращает новый объект класса  TreeWalker.

Синтаксис

document.createTreeWalker(root, whatToShow[, filter[, entityReferenceExpansion]]);

Параметры

root
корневой узел Node для TreeWalker. Чаще всего это элемент принадлежащий document.
whatToShow Необязательный
A unsigned long representing a bitmask created by combining the constant properties of NodeFilter. It is a convenient way of filtering for certain types of node. It defaults to 0xFFFFFFFF representing the SHOW_ALL constant.
Константа Числовое значение Описание
NodeFilter.SHOW_ALL -1 (that is the max value of unsigned long) Показывать все узлы.
NodeFilter.SHOW_ATTRIBUTE Это устаревшее API больше не должно использоваться, но оно по-прежнему может работать. 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 Это устаревшее API больше не должно использоваться, но оно по-прежнему может работать. 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 Это устаревшее API больше не должно использоваться, но оно по-прежнему может работать. 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 Это устаревшее API больше не должно использоваться, но оно по-прежнему может работать. 16 Shows EntityReference nodes.
NodeFilter.SHOW_NOTATION Это устаревшее API больше не должно использоваться, но оно по-прежнему может работать. 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.
filter Необязательный
A NodeFilter, that is an object with a method acceptNode, which is called by the TreeWalker to determine whether or not to accept a node that has passed the whatToShow check.
entityReferenceExpansion Необязательный Этот API вышел из употребления и его работа больше не гарантируется.
A Boolean flag indicating if when discarding an EntityReference 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);

Specifications

Specification Status Comment
DOM
Определение 'Document.createTreeWalker' в этой спецификации.
Живой стандарт Removed the expandEntityReferences parameter. Made the whatToShow and filter parameters optionals.
Document Object Model (DOM) Level 2 Traversal and Range Specification
Определение 'Document.createTreeWalker' в этой спецификации.
Устаревшая Initial definition

Browser compatibility

BCD tables only load in the browser

See also

  • The interface of the object it creates: TreeWalker.