code: public Node nextNode() throws DOMException
    {
  
      if ((m_next) < this.size())
      {
        Node next = this.elementAt(m_next);
  
        m_next++;
  
        return next;
      }
      else
        return null;
    }
docs: Returns the next node in the set and advances the position of the
  iterator in the set. After a NodeIterator is created, the first call
  to nextNode() returns the first node in the set.
  @return  The next <code>Node</code> in the set being iterated over, or
  <code>null</code> if there are no more members in that set.
  @throws DOMException
  INVALID_STATE_ERR: Raised if this method is called after the
  <code>detach</code> method was invoked.