TreeWalker.whatToShow

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TreeWalker.whatToShow read-only property returns an unsigned long being a bitmask made of constants describing the types of 节点 that must to be presented. Non-matching nodes are skipped, but their children may be included, if relevant. The possible values are:

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。

句法

nodeTypes = treeWalker.whatToShow;

范例

var treeWalker = document.createTreeWalker(
    document.body,
    NodeFilter.SHOW_ELEMENT + NodeFilter.SHOW_COMMENT + NodeFilter.SHOW_TEXT,
    { acceptNode: function(node) { return NodeFilter.FILTER_ACCEPT; } },
    false
);
if( (treeWalker.whatToShow == NodeFilter.SHOW_ALL) ||
    (treeWalker.whatToShow % (NodeFilter.SHOW_COMMENT*2)) >= NodeFilter.SHOW_COMMENT) {
    // treeWalker will show comments
}

规范

规范	状态	注释
DOM The definition of 'TreeWalker.whatToShow' in that specification.	实时标准	无变化自 Document Object Model (DOM) Level 2 Traversal and Range Specification
Document Object Model (DOM) Level 2 Traversal and Range Specification The definition of 'TreeWalker.whatToShow' 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
`whatToShow`	Chrome 1	Edge 12	Firefox 4	IE 9	Opera 9	Safari 3	WebView Android 3	Chrome Android Yes	Firefox Android 4	Opera Android 10.1	Safari iOS 3	Samsung Internet Android Yes

图例

完整支持

另请参阅

TreeWalker 接口。

元数据

最后修改： 2019 年 3 月 23 日

DOM (文档对象模型)
TreeWalker
特性
1. currentNode
2. ~~expandEntityReferences~~
3. filter
4. root
5. whatToShow
方法
DOM 相关页面

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