TreeWalker.whatToShow

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 Legacy, no more used.
NodeFilter.SHOW_ENTITY_REFERENCE 16 Legacy, no more used.
NodeFilter.SHOW_NOTATION 2048 Legacy, no more used.
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
DOM Standard (DOM)
# dom-treewalker-whattoshow

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
whatToShow
1
12
4
9
9
3
3
18
4
10.1
3
1.0

See also

© 2005–2021 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/TreeWalker/whatToShow