HTML DOM TreeWalker whatToShow property

Last Updated : 11 Jul, 2022

The TreeWalker whatToShow property returns an unsigned Integer describing the type of Node that must to be presented. This is a read-only property.

Syntax:

whatToShow = treeWalker.whatToShow;

Return Value: This property returns an unsigned Integer describing the type of Node that must be presented.

following are the possible values of unsigned constant.

Constant	Return Value	Constant Description
NodeFilter.SHOW_ALL	1	Shows all 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_PROCESSING_INSTRUCTION	64	Shows ProcessingInstruction nodes.
NodeFilter.SHOW_TEXT	4	Shows Text nodes.

Example: This example has NodeFilter.FILTER_ACCEPT as node filter and hence returns whatToShow value respectively.

HTML

<!doctype html>
<html>
<head>
    <meta charset="utf-8">
<title>HTML DOM TreeWalker whatToShow property</title>    
</head>
<body>
    <h1>GeeksforGeeks</h1>
    <p>Click Below</p>
    <button onclick="get()">Click</button>
</body>
<script>
        var treeWalker = 
document.createTreeWalker(document.head,NodeFilter.SHOW_DOCUMENT_TYPE,
        { acceptNode: function(node) {
          return NodeFilter.FILTER_ACCEPT; } },
    false
);
        function get(){
            node = treeWalker.whatToShow;
            console.log(treeWalker)
            console.log(node);
        }
</script>
</html>