这个weblogging 设计得比较精巧

				/*
				 * Attr.js
				 * An attribute node in an XML document
				 *
				 * Copyright (C) 2001 David A. Lindquist (dave@gazingus.org)
				 *
				 * This library is free software; you can redistribute it and/or modify
				 * it under the terms of the GNU Lesser General Public License as published by
				 * the Free Software Foundation; either version 2.1 of the License, or
				 * (at your option) any later version.
				 * 
				 * This library is distributed in the hope that it will be useful,
				 * but WITHOUT ANY WARRANTY; without even the implied warranty of
				 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
				 * GNU Lesser General Public License for more details.
				 * 
				 * You should have received a copy of the GNU Lesser General Public License
				 * along with this library; if not, write to the Free Software
				 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
				 */
				
				Attr.prototype = new Node();
				Attr.prototype.constructor = Attr;
				  // Attr : Node
				
				function Attr( ownerDoc, name ) {
				  this.name = name;
				  this.specified = true;
				  this.value = null;
				  
				  // inherited from Node
				  this.childNodes = new NodeList();
				  this.nodeName = name;
				  this.nodeType = Node.ATTRIBUTE_NODE;
				  this.nodeValue = null;
				  this.ownerDocument = ownerDoc;
				}
				
				Attr.prototype.getName =
				function() {
				  return this.name;
				}
				
				Attr.prototype.getNodeValue =
				function() {
				  return this.getValue();
				}
				
				Attr.prototype.getSpecified =
				function() {
				  return this.specified;
				}
				
				Attr.prototype.getValue =
				function() {
				  // :REVISIT:
				  var value = "";
				  for ( var i = 0; i < this.childNodes.length; i++ ) {
				    value += this.childNodes.item(i).getNodeValue();
				  }
				  return value;
				}
				
				Attr.prototype.setValue =
				function( value ) {
				  // :REVISIT:
				  this.childNodes = new NodeList();
				  this.firstChild = null;
				  this.lastChild = null;
				  
				  if ( value != null ) {
				    this.appendChild( this.ownerDocument.createTextNode( value ) );
				  }
				}