jquery省市联动，根据公司需求而写

 //author:guan
 //2015-05-25
 //省市联动
 //实用说明，页面引用如下js
 //<script src="../js/jquery-1.6.3.min.js"></script>
 //<script src="js/ProvinceDropDown.js"></script>
 //页面元素
 //<select id="Province"></select>
 //<select id="City"></select>

 $(function () {
     //初始化下拉框值
     InitDropDown("Province", "City");
 })
 var Dropdowndata = [{ "ParentName": "宁夏", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "银川", "ChildrenCode": "11" }] }, { "ParentName": "山东", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "济南", "ChildrenCode": "11" }, { "ChildrenName": "青岛", "ChildrenCode": "12" }, { "ChildrenName": "潍坊", "ChildrenCode": "13" }] }, { "ParentName": "甘肃", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "兰州", "ChildrenCode": "11" }] }, { "ParentName": "天津", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "天津", "ChildrenCode": "11" }] }, { "ParentName": "湖南", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "长沙", "ChildrenCode": "11" }] }, { "ParentName": "湖北", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "武汉", "ChildrenCode": "11" }, { "ChildrenName": "襄阳", "ChildrenCode": "12" }] }, { "ParentName": "云南", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "昆明", "ChildrenCode": "11" }] }, { "ParentName": "广东", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "广州", "ChildrenCode": "11" }, { "ChildrenName": "深圳", "ChildrenCode": "12" }, { "ChildrenName": "佛山", "ChildrenCode": "13" }, { "ChildrenName": "东莞", "ChildrenCode": "14" }, { "ChildrenName": "中山", "ChildrenCode": "15" }] }, { "ParentName": "浙江", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "杭州", "ChildrenCode": "11" }, { "ChildrenName": "宁波", "ChildrenCode": "12" }, { "ChildrenName": "嘉兴", "ChildrenCode": "13" }, { "ChildrenName": "绍兴", "ChildrenCode": "14" }, { "ChildrenName": "义乌", "ChildrenCode": "15" }, { "ChildrenName": "温州", "ChildrenCode": "16" }, { "ChildrenName": "台州", "ChildrenCode": "17" }] }, { "ParentName": "江西", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "南昌", "ChildrenCode": "11" }] }, { "ParentName": "*", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "乌鲁木齐", "ChildrenCode": "11" }] }, { "ParentName": "北京", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "北京", "ChildrenCode": "11" }] }, { "ParentName": "河北", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "唐山", "ChildrenCode": "11" }, { "ChildrenName": "保定", "ChildrenCode": "12" }, { "ChildrenName": "邯郸", "ChildrenCode": "13" }] }, { "ParentName": "贵州", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "贵阳", "ChildrenCode": "11" }] }, { "ParentName": "四川", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "成都", "ChildrenCode": "11" }, { "ChildrenName": "南充", "ChildrenCode": "12" }, { "ChildrenName": "泸州", "ChildrenCode": "13" }, { "ChildrenName": "宜宾", "ChildrenCode": "14" }, { "ChildrenName": "绵阳", "ChildrenCode": "15" }] }, { "ParentName": "吉林", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "长春", "ChildrenCode": "11" }] }, { "ParentName": "安徽", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "合肥", "ChildrenCode": "11" }, { "ChildrenName": "芜湖", "ChildrenCode": "12" }] }, { "ParentName": "黑龙江", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "哈尔滨", "ChildrenCode": "11" }] }, { "ParentName": "辽宁", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "沈阳", "ChildrenCode": "11" }, { "ChildrenName": "大连", "ChildrenCode": "12" }] }, { "ParentName": "山西", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "山西", "ChildrenCode": "11" }] }, { "ParentName": "河南", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "郑州", "ChildrenCode": "11" }] }, { "ParentName": "福建", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "福州", "ChildrenCode": "11" }, { "ChildrenName": "厦门", "ChildrenCode": "12" }, { "ChildrenName": "泉州", "ChildrenCode": "13" }] }, { "ParentName": "重庆", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "重庆", "ChildrenCode": "11" }] }, { "ParentName": "江苏", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "南京", "ChildrenCode": "11" }, { "ChildrenName": "苏州", "ChildrenCode": "12" }, { "ChildrenName": "无锡", "ChildrenCode": "13" }, { "ChildrenName": "常州", "ChildrenCode": "14" }, { "ChildrenName": "南通", "ChildrenCode": "15" }, { "ChildrenName": "扬州", "ChildrenCode": "16" }, { "ChildrenName": "盐城", "ChildrenCode": "17" }] }, { "ParentName": "陕西", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "西安", "ChildrenCode": "11" }, { "ChildrenName": "榆林", "ChildrenCode": "12" }] }, { "ParentName": "广西", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "南宁", "ChildrenCode": "11" }] }, { "ParentName": "海南", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "海口", "ChildrenCode": "11" }] }, { "ParentName": "上海", "ParentCode": "1", "ChildrenNodes": [{ "ChildrenName": "上海", "ChildrenCode": "11" }] }];

 function InitDropDown(province, city) {
     var _province = $("#" + province);
     //初始化清空，为其添加请选择默认选项
     _province.empty().append($("<option>").text("请选择").val("-1"));

     var _city = $("#" + city);
     _city.empty().append($("<option>").text("请选择").val("-1"));
     //循环读取数组的json一级下拉值
     for (var i = 0; i < Dropdowndata.length; i++) {
         var option = $("<option>").text(Dropdowndata[i].ParentName).val(Dropdowndata[i].ParentCode).attr("pos", i);
         _province.append(option);
     }
     $(_province).change(function () {
         _city.empty().append($("<option>").text("请选择").val("-1"));
         //根据数组下标从数据取出json数据
         var citys = Dropdowndata[$(this).find("option:selected").attr("pos")].ChildrenNodes;
         for (var i = 0; i < citys.length; i++) {
             var option = $("<option>").text(citys[i].ChildrenName).val(citys[i].ChildrenCode);
             _city.append(option);
         }
     })
 } 

页面元素如下

  <select id="Province"></select>
         <select id="City"></select>