NodeFilter

A NodeFilter interface represents an object used to filter the nodes in a NodeIterator or TreeWalker. A NodeFilter knows nothing about the document or traversing nodes; it only knows how to evaluate a single node against the provided filter.

Note: The browser doesn't provide any object implementing this interface. It is the user who is expected to write one, tailoring the acceptNode() method to its needs, and using it with some TreeWalker or NodeIterator objects.

Properties

This interface neither implements nor inherits any properties.

Methods

This interface doesn't inherit any methods.

NodeFilter.acceptNode()

Returns an unsigned short that will be used to tell if a given Node must be accepted or not by the NodeIterator or TreeWalker iteration algorithm.

This method is expected to be written by the user of a NodeFilter. Possible return values are:

Constant Description
FILTER_ACCEPT Value returned by the NodeFilter.acceptNode() method when a node should be accepted.
FILTER_REJECT

Value to be returned by the NodeFilter.acceptNode() method when a node should be rejected. For TreeWalker, child nodes are also rejected.

For NodeIterator, this flag is synonymous with FILTER_SKIP.

FILTER_SKIP

Value to be returned by NodeFilter.acceptNode() for nodes to be skipped by the NodeIterator or TreeWalker object.

The children of skipped nodes are still considered. This is treated as "skip this node but not its children".

Example

const nodeIterator = document.createNodeIterator(
  // Node to use as root
  document.getElementById('someId'),

  // Only consider nodes that are text nodes (nodeType 3)
  NodeFilter.SHOW_TEXT,

  // Object containing the function to use for the acceptNode method
  // of the NodeFilter
    { acceptNode: function(node) {
      // Logic to determine whether to accept, reject or skip node
      // In this case, only accept nodes that have content
      // other than whitespace
      if ( ! /^\s*$/.test(node.data) ) {
        return NodeFilter.FILTER_ACCEPT
      }
    }
  },
  false
);

// Show the content of every non-empty text node that is a child of root
let node;

while ((node = nodeIterator.nextNode())) {
  alert(node.data)
}

Specifications

Specification Status Comment
DOM
The definition of 'NodeFilter' in that specification.
Living Standard
Document Object Model (DOM) Level 2 Traversal and Range Specification
The definition of 'NodeFilter' in that specification.
Obsolete Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
NodeFilterChrome Full support 1Edge Full support 12Firefox Full support 2IE Full support 9Opera Full support 9Safari Full support 3WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 3Samsung Internet Android Full support Yes
acceptNodeChrome Full support 1Edge Full support 12Firefox Full support 2IE Full support 9Opera Full support 9Safari Full support 3WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 3Samsung Internet Android Full support Yes

Legend

Full support
Full support

See also