/**
 * 初始化地州列表
 * 
 * @return
 */
public String initDistrict()
{
    // 子属地subCityList
    List<Map> subCityList = new ArrayList<Map>();
    subCityList = ResTool.getSubCityList(fo.getCityId(), 1, false);
    ajax = appendDistrict(subCityList);
    return "ajax";
}
/**
 * 初始化地州下拉框
 * 
 * @param list
 * @return
 */
@SuppressWarnings("rawtypes")
private String appendDistrict(List<Map> list)
{
    StringBuilder sb = new StringBuilder();
    if (list == null || list.size() == 0)
    {
        sb.append("<option value='-1'>==无数据==</option>");
        return sb.toString();
    }
    else
    {
        sb.append("<option value='-1'>==请选择==</option>");
        for (Map map : list)
        {
            String cityId = String.valueOf(map.get("city_id"));
            String cityName = String.valueOf(map.get("city_name"));
            if ("00".equals(cityId))
            {
                sb.append("省中心");
            }
            else
            {
                sb.append("<option value='").append(cityId).append("'>")
                        .append(cityName).append("</option>");
            }
        }
    }
    return sb.toString();
}
jsp页面：
//初始化区县
function init(){
    if($("#cityId").val()!=null && $("#cityId").val()!=-1)
    {
        $.ajax({
            type:"POST",
            url:"<s:url value='/liposs/warn/report/highratewarnhousereport/HighRateWarnHouseAction!initDistrict.action'/>",
            data:{ 
                "cityId":$("#cityId").val()
            },
            success:function(data){
                $("select[name='subCityId']").html(data);
            },
            error: function(req, text, err){        
                alert("获取后台数据异常("+text+"),\n请跟管理员联系.");
            }
        }); 

   }else{
        $("select[name='subCityId']").html("<option value='-1'>===请先选择属地===</option>");
   }
}
<tr>
    <td class="title_2" width="15%" align="center">属地</td>
    <td width="15%" colspan="2" align="left">
        <select id="cityId" name="cityId" onchange="init();">
            <option value="-1">==请选择==</option>
                <s:iterator id="ct" value="cityList">
                    <option value="<s:property value="#ct.city_id"/>">
                        <s:property value="#ct.city_name" />
                    </option>
                </s:iterator>
        </select> 
        &nbsp;&nbsp;&nbsp;&nbsp;当前所选属地为：
        <select id="subCityId" name="subCityId" >
            <option value="-1">===请先选择属地===</option>
        </select> (地州)
    </td>
</tr>