TreeWalker

TreeWalker 对象表示一个当前文档的子树中的所有节点及其位置。

可以使用Document.createTreeWalker() 方法创建一个TreeWalker。

属性

本接口未继承任何属性

TreeWalker.root 只读

返回一个 Node 表示创建时所使用的根节点。

TreeWalker.whatToShow 只读

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

Constant	数值	描述
NodeFilter.SHOW_ALL	-1 (that is the max value of unsigned long)	显示所有节点
NodeFilter.SHOW_ATTRIBUTE	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	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	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	16	Shows EntityReference nodes.
NodeFilter.SHOW_NOTATION	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.

TreeWalker.filter 只读

根据不同的 节点过滤器返回 相关节点.

TreeWalker.expandEntityReferences 只读

Is a Boolean indicating if, when discarding an EntityReference its whole sub-tree must be discarded at the same time.

TreeWalker.currentNode

任何遍历方法在上一次遍历中返回的节点 .

方法

此接口不继承任何方法。

TreeWalker.parentNode()

遍历到当前 节点的父节点, 并返回. It also moves the current node to this one. If no such node exists, or if it is before that the root node defined at the object construction, returns null and the current node is not changed.

TreeWalker.firstChild()

遍历到当前 节点的第一个子节点, 并返回. It also moves the current node to this child. If no such child exists, returns null and the current node is not changed.

TreeWalker.lastChild()

遍历到当前 节点的最后一个子节点, 并返回. It also moves the current node to this child. If no such child exists, returns null and the current node is not changed.

TreeWalker.previousSibling()

遍历到当前 节点的前一个兄弟节点, 并返回. If there is no such node, return null and the current node is not changed.

TreeWalker.nextSibling()

遍历到当前 节点的后一个兄弟节点, 并返回.. If there is no such node, return null and the current node is not changed.

TreeWalker.previousNode()

Moves the current Node to the previous visible node in the document order, and returns the found node. It also moves the current node to this one. If no such node exists,or if it is before that the root node defined at the object construction, returns null and the current node is not changed.

TreeWalker.nextNode()

Moves the current Node to the next visible node in the document order, and returns the found node. It also moves the current node to this one. If no such node exists, returns null and the current node is not changed.

Specifications

Browser compatibility

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See also

• The creator method: Document.createTreeWalker().
• Related interfaces: NodeFilter, NodeIterator.