Document.createTreeWalker()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨июль 2015 г.⁩.

Вызов методаDocument.createTreeWalker() возвращает новый объект классаTreeWalker.

Синтаксис

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

Параметры

root

корневой узелNode дляTreeWalker. Чаще всего это элемент принадлежащий document.

whatToShowНеобязательный

Aunsigned 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 of`unsigned long`)	Показывать все узлы.
`NodeFilter.SHOW_ATTRIBUTE`Устарело	`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`Устарело	`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`Устарело	`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`Устарело	`16`	Shows`EntityReference` nodes.
`NodeFilter.SHOW_NOTATION`Устарело	`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.

filterНеобязательный

ANodeFilter, 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.

entityReferenceExpansionНеобязательный

ABoolean flag indicating if when discarding anEntityReference its whole sub-tree must be discarded at the same time.

Return value

A newTreeWalker 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 theacceptNode() 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);