Document.createTreeWalker()

在此页

句法
范例
规范
浏览器兼容性
另请参阅
相关话题

Document.createTreeWalker() creator method returns a newly created TreeWalker 对象。

句法

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

参数

root

A root


									节点

of this


									TreeWalker

traversal. Typically this will be an element owned by the document.

whatToShow 可选


								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

表示


								SHOW_ALL

常量。

常量	数值	描述
`NodeFilter.SHOW_ALL`	`-1` (that is the max value of `unsigned long` )	展示所有节点。
`NodeFilter.SHOW_ATTRIBUTE`	`2`	Shows attribute `Attr` nodes. This is meaningful only when creating a `TreeWalker` 采用 `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`	`8`	展示 `CDATASection` 节点。
`NodeFilter.SHOW_COMMENT`	`128`	展示 `注释` 节点。
`NodeFilter.SHOW_DOCUMENT`	`256`	展示 `Document` 节点。
`NodeFilter.SHOW_DOCUMENT_FRAGMENT`	`1024`	展示 `DocumentFragment` 节点。
`NodeFilter.SHOW_DOCUMENT_TYPE`	`512`	展示 `DocumentType` 节点。
`NodeFilter.SHOW_ELEMENT`	`1`	展示 `元素` 节点。
`NodeFilter.SHOW_ENTITY`	`32`	展示 `Entity` nodes. This is meaningful only when creating a `TreeWalker` 采用 `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`	`16`	展示 `EntityReference` 节点。
`NodeFilter.SHOW_NOTATION`	`2048`	展示 `Notation` nodes. This is meaningful only when creating a `TreeWalker` 采用 `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`	展示 `ProcessingInstruction` 节点。
`NodeFilter.SHOW_TEXT`	`4`	展示 `文本` 节点。

filter 可选


									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 可选


									布尔

flag indicating if when discarding an


									EntityReference

its whole sub-tree must be discarded at the same time.

返回值

新的 TreeWalker 对象。

范例

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 = [];
var currentNode = treeWalker.currentNode;
while(currentNode) {
  nodeList.push(currentNode);
  currentNode = treeWalker.nextNode();
}

规范

规范	状态	注释
DOM The definition of 'Document.createTreeWalker' in that specification.	实时标准	移除 `expandEntityReferences` parameter. Made the `whatToShow` and `filter` parameters optionals.
Document Object Model (DOM) Level 2 Traversal and Range Specification The definition of 'Document.createTreeWalker' in that specification.	过时	初始定义

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`createTreeWalker`	Chrome 1	Edge 12	Firefox 2	IE 9	Opera 9	Safari 3	WebView Android Yes	Chrome Android Yes	Firefox Android 4	Opera Android 10.1	Safari iOS 3	Samsung Internet Android Yes
`expandEntityReferences` 参数	Chrome 4	Edge 12	Firefox 2 — 12	IE 9	Opera 9	Safari 3	WebView Android Yes	Chrome Android Yes	Firefox Android 4 — 14	Opera Android Yes	Safari iOS 3	Samsung Internet Android Yes
`whatToShow` and `filter` optional	Chrome 4	Edge ≤79	Firefox 12	IE No	Opera Yes	Safari 3	WebView Android Yes	Chrome Android Yes	Firefox Android 14	Opera Android Yes	Safari iOS 3	Samsung Internet Android Yes

图例

完整支持
不支持

另请参阅

The interface of the object it creates: TreeWalker .

元数据

最后修改： Jan 21, 2020

在此页

句法

参数

返回值

范例

规范

浏览器兼容性

图例

另请参阅

相关话题