function querySub(id,sid/*选中的项*/){ $.post('${path}/page/article/querySubChannelArticle.action',                 {'channelId':id},function(data){                     $('select[name="article.subChannel.subId"] option[value!=""]').remove();                     var jsonObj = data;                        for ( var i = 0; i < jsonObj.length; i++) {                         var $option = $('<option>');                         $option.attr('value',jsonObj[i].subId);                         if(jsonObj[i].subId === sid){                             $option.attr('selected',true);                         }                         $option.text(jsonObj[i].subName);                         $('select[name="article.subChannel.subId"]').append($option);                     }                 });         }         $(function(){             querySub(<s:property value='article.subChannel.channel.channelId'/>,<s:property value='article.subChannel.subId'/>);         });  

<tr>                     <th>一级栏目</th>                           <td valign="middle">                             <s:select id='_channel' list="channelList" listKey="channelId"                                 listValue="channelName"                                  key="article.subChannel.channel.channelId"                                 onchange="querySub(this.value)"></s:select>                           </td>                  </tr>                  <tr>                     <th>二级栏目</th>                           <td valign="middle">                           <s:select name='article.subChannel.subId' list="{}" headerKey="" headerValue="-请选择-"></s:select>                           <!--<s:property value="article.subChannel.subName"/>                           --></td>                  </tr>

 public String querySubChannelArticle(){          HttpServletResponse response=getResponse();         HttpServletRequest request=getRequest();         response.setContentType("application/json; charset=UTF-8");         PrintWriter out =null;         try {             out = response.getWriter();             List<Map<String,Object>> list = new LinkedList<Map<String,Object>>();             if(channelId!=null && !channelId.equals("")){                 Channel tmp = new Channel();                 tmp.setChannelId(Integer.parseInt(channelId));                 subChannelList = subChannelDAO.listSubChannel(tmp);                 for(Object oo:subChannelList){                     Map<String,Object> obj = new HashMap<String,Object>();                     SubChannel c = (SubChannel)oo;                     obj.put("subId", c.getSubId());                     obj.put("subName", c.getSubName());                     list.add(obj);                 }             }             String outStr = JsonUtil.toJSONStr(list);             out.println(outStr);         }catch(Exception e){         e.printStackTrace();         }         out.flush();         out.close();         return null;     }