Revision 749289 of NodeFilter

<div>{{APIRef("DOM")}}</div>

<p>A <strong><code>NodeFilter</code></strong> interface represents an object used to filter the nodes in a {{ domxref("NodeIterator") }} or {{ domxref("TreeWalker") }}. They don't know anything about the DOM or how to traverse nodes; they just know how to evaluate a single node against the provided filter.</p>

<div class="note">
<p>The browser doesn't provide any object implementing this interface. It is the user who is expected to write one, tailoring the <code>acceptNode()</code> method to its needs, and using it with some {{domxref("TreeWalker")}} or {{domxref("NodeIterator")}} objects.</p>
</div>

<h2 id="Properties">Properties</h2>

<p><em>This interface neither implements, nor inherits, any property.</em></p>

<h2 id="Methods">Methods</h2>

<p><em>This interface doesn't inherit any method.</em></p>

<dl>
 <dt>{{domxref("NodeFilter.acceptNode()")}}</dt>
 <dd>Returns an <code>unsigned short</code> that will be used to tell if a given {{domxref("Node")}} must be accepted or not by the {{ domxref("NodeIterator") }} or {{ domxref("TreeWalker") }} iteration algorithm. This method is expected to be written by the user of a <code>NodeFilter</code>. Possible return values are:
 <table class="standard-table">
  <tbody>
   <tr>
    <td class="header">Constant</td>
    <td class="header">Description</td>
   </tr>
   <tr>
    <td><code>FILTER_ACCEPT</code></td>
    <td>Value returned by the {{ domxref("NodeFilter.acceptNode()") }} method when a node should be accepted.</td>
   </tr>
   <tr>
    <td><code>FILTER_REJECT</code></td>
    <td>Value to be returned by the {{ domxref("NodeFilter.acceptNode()") }} method when a node should be rejected. The children of rejected nodes are not visited by the {{ domxref("NodeIterator") }} or {{ domxref("TreeWalker") }} object; this value is treated as "skip this node and all its children".</td>
   </tr>
   <tr>
    <td><code>FILTER_SKIP</code></td>
    <td>Value to be returned by {{ domxref("NodeFilter.acceptNode()") }} for nodes to be skipped by the {{ domxref("NodeIterator") }} or {{ domxref("TreeWalker") }} object. The children of skipped nodes are still considered. This is treated as "skip this node but not its children".</td>
   </tr>
  </tbody>
 </table>
 </dd>
</dl>

<h2 id="Example">Example</h2>

<pre class="brush: js">
var 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
var node;

while ((node = nodeIterator.nextNode())) {
  alert(node.data);
}
</pre>

<h2 id="Specification" name="Specification">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('DOM WHATWG', '#nodeFilter', 'NodeFilter')}}</td>
   <td>{{Spec2('DOM WHATWG')}}</td>
   <td>&nbsp;</td>
  </tr>
  <tr>
   <td>{{SpecName('DOM2 Traversal_Range', 'traversal.html#Traversal-NodeFilter', 'NodeFilter')}}</td>
   <td>{{Spec2('DOM2 Traversal_Range')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{CompatibilityTable}}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>1.0</td>
   <td>{{CompatGeckoDesktop("1.8.1")}}</td>
   <td>9.0</td>
   <td>9.0</td>
   <td>3.0</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoMobile("1.8.1")}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>9.0</td>
   <td>3.0</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li>Related interfaces: {{domxref("TreeWalker")}}, {{domxref("NodeIterator")}}.</li>
</ul>