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:

ConstantNumerical valueDescription
NodeFilter.SHOW_ALL-1 (that is the max value of unsigned long)Shows all nodes.
NodeFilter.SHOW_ATTRIBUTE This deprecated API should no longer be used, but will probably still work.2Shows 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 This deprecated API should no longer be used, but will probably still work.8Shows CDATASection nodes.
NodeFilter.SHOW_COMMENT128Shows Comment nodes.
NodeFilter.SHOW_DOCUMENT256Shows Document nodes.
NodeFilter.SHOW_DOCUMENT_FRAGMENT1024Shows DocumentFragment nodes.
NodeFilter.SHOW_DOCUMENT_TYPE512Shows DocumentType nodes.
NodeFilter.SHOW_ELEMENT1Shows Element nodes.
NodeFilter.SHOW_ENTITY This deprecated API should no longer be used, but will probably still work.32Shows 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 This deprecated API should no longer be used, but will probably still work.16Shows EntityReference nodes.
NodeFilter.SHOW_NOTATION This deprecated API should no longer be used, but will probably still work.2048Shows 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_INSTRUCTION64Shows ProcessingInstruction nodes.
NodeFilter.SHOW_TEXT4Shows 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

SpecificationStatusComment
DOM
The definition of 'TreeWalker.whatToShow' in that specification.
Living StandardNo 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.
ObsoleteInitial definition.

Browser compatibility

BCD tables only load in the browser

See also

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