Lets applications examine nodes as they are being constructed during a parse.
As each node is examined, it may be modified or removed, or parsing may be aborted.
Java Binding:
package org.w3c.dom.ls;
public interface LSParserFilter {
    // Constants returned by startElement and acceptNode
  public static final short FILTER_ACCEPT    = 1;
  public static final short FILTER_REJECT    = 2;
  public static final short FILTER_SKIP      = 3;
  public static final short FILTER_INTERRUPT = 4;
  public short startElement(Element element);
  public short acceptNode(Node node);
  public int   getWhatToShow();
}