mvc三级联运做法，直接贴代码

  $(document).ready(function () {
        GetByJquery();
        $("#s1").change(function () {
            
            GetCity()
        });
        $("#s2").change(function () { GetStation() });      
       
    });

    function GetByJquery() {

        $("#s1").empty(); //清空省份SELECT控件
      
        $.getJSON("resource/SendStation/GetProvinceList", function (data) {
            $.each(data, function (i, item) {
               
                $("<option></option>")
                    .val(item['Value'])
                    .text(item['Text'])
                    .appendTo($("#s1"));
            });
            GetCity();
        });
    }
        function GetCity() {          
            $("#s2").empty(); //清空城市SELECT控件
            var url = "resource/SendStation/GetCityList/?pid=" + $("#s1").val();
            $.getJSON(url, function (data) {
                $.each(data, function (i, item) {
                    $("<option></option>")
                         .val(item['Value'])
                         .text(item['Text'])
                        .appendTo($("#s2"));
                });
                GetStation();
            });
        }

        function GetStation() {
            $("#s3").empty(); //清空站点SELECT控件
            var url = "resource/SendStation/GetStationList/?cid=" + $("#s2").val();
            $.getJSON(url, function (data) {
                $.each(data, function (i, item) {
                    $("<option></option>")
                          .val(item['Value'])
                          .text(item['Text'])
                        .appendTo($("#s3"));
                });
            });
        }


 /// <summary>
        /// 获取所有［省份］数据
        /// </summary>
        public JsonResult GetProvinceList()
        {
            List<TrainStation> modellist = ResourceRule.GetProvinceList();

            List<SelectListItem> items = new List<SelectListItem>();
            foreach (var tem in modellist)
            {
                items.Add(new SelectListItem { Text = tem.TSProvinceName, Value = tem.TSProvinceId.ToString() });
            }

            return Json(items, JsonRequestBehavior.AllowGet);
        }

        public JsonResult GetCityList(int pid)
        {
            List<TrainStation> modellist = ResourceRule.GetCityList(pid);
            List<SelectListItem> items = new List<SelectListItem>();
            foreach (var tem in modellist)
            {
                items.Add(new SelectListItem { Text = tem.TSCityName, Value = tem.TSCityId.ToString() });
            }

            return Json(items, JsonRequestBehavior.AllowGet);
        }

        public JsonResult GetStationList(int cid)
        {

            List<TrainStation> modellist = ResourceRule.GetStationList(cid);
            List<SelectListItem> items = new List<SelectListItem>();
            foreach (var tem in modellist)
            {
                items.Add(new SelectListItem { Text = tem.TSName, Value = tem.TSId.ToString() });
            }

            return Json(items, JsonRequestBehavior.AllowGet);

        }