TreeWalker.whatToShow - Web APIs 编辑
The TreeWalker.whatToShow
read-only property 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 | Numerical value | Description |
NodeFilter.SHOW_ALL | -1 (that is the max value of unsigned long ) | Shows all nodes. |
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. |
Syntax
nodeTypes = treeWalker.whatToShow;
Example
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
}
Specifications
Specification | Status | Comment |
---|---|---|
DOM The definition of 'TreeWalker.whatToShow' in that specification. | Living Standard | No change from 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. | Obsolete | Initial definition. |
Browser compatibility
BCD tables only load in the browser
See also
- The
TreeWalker
interface.
如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱,如果其他用户或者作者回复了您的评论,将不能在第一时间通知您!
发布评论