一个下拉框的赋值小案例

<li>
                 <label>&nbsp;&nbsp;司法机构：</label>
                 <select id="chooseAgency" class="" name="chooseAgency" style="width: 160px; height: 20px;"></select>
                </li>

var getAgencyId=function(){
        var agencyId=$("#chooseAgency  option:selected").val();
        if(agencyId==-1){
            agencyId="";
        }
        return agencyId;
    };    

function initAgency(){
    var cAgency=$("#chooseAgency") ;
    $.ajax({
        type: 'post',
        dataType: 'json',
        async: false,
        url: parent.baseUrl+"report/initAgency",
        success: function (result) {
            var size=result.length ;
            var opt='<option  value="-1" selected="selected">显示全部</option>';
            if(size==0){
                cAgency.html(opt);
                return ;
            }
            $.each(result,function(i,item){
                opt+='<option  value="'+item.key+'" >'+item.name+'</option>';
            });
            cAgency.html(opt);
            return ;
        }    
    });    
}

@RequestMapping(value = "initAgency", method = RequestMethod.POST)
    @ResponseBody
    public List<TypeModel> reportAgency(@ModelAttribute("selectedAgency") SysAgencyDto selectedAgency){
        Long agencyId= selectedAgency.getId();
        List<TypeModel> dtoList=new ArrayList<TypeModel>();//当前机构数据放在第一个位置
        List<SysAgency> all=new ArrayList<SysAgency>();
        SysAgencyDtoAssembler dtoassembler=new SysAgencyDtoAssembler();
        if(agencyId==0l){
           all=sysAgencyService.findAll(null);
        }else{
            SysAgency agency=sysAgencyService.findOne(agencyId);
            dtoList.add(dtoassembler.toDic(agency));            
            all=aucReportService.findAllSubAgency(all,agencyId);
        }
        for (SysAgency sysAgency : all) {
            dtoList.add(dtoassembler.toDic(sysAgency));
        }
       return  dtoList;
    }