ajax.net +jquery 无刷新三级联动的实例代码

    <!doctype html public "-//w3c//dtd xhtml 1.0 transitional//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <script src="jquery1.7.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(function () {
            $.ajax({
                type: "post",
                contenttype: "application/json",
                url: "webservice1.asmx/loadprovince",
                data: "{}",
                success: function (result) {
                    var ping;
                    for (var i = 0; i < result.d.length; i++) {
                        ping += "<option value=" + result.d[i].provinceid + ">";
                        ping += result.d[i].provincename;
                        ping += "</option>";

}
$('#select1').append(ping);

}

            })
            $('#select1').change(function () {
                //第二次选时要记得清空市和县中的内容
                $('#select2 option:gt(0)').remove();
                $('#select3 option:gt(0)').remove();
                //在省的改变事件里绑定下一个下来列表（要失掉省的id）

                $.ajax({
                    type: "post",
                    contenttype: "application/json",
                    url: "webservice1.asmx/loadcity",
                    data: "{fatherid:'" + $('#select1 option:selected').val() + "'}",
                    success: function (result) {
                        var str2;
                        for (var i = 0; i < result.d.length; i++) {
                            str2 += "<option value=" + result.d[i].cityid + ">";
                            str2 += result.d[i].cityname;
                            str2 += "</option>";
                        }

                        $('#select2').append(str2);
                    }
                })
            })
            $('#select2').change(function () {
                $('#select3 option:gt(0)').remove();

                $.ajax({
                    type: "post",
                    contenttype: "application/json",
                    url: "webservice1.asmx/loadarea",
                    data: "{fatherid:'" + $('#select2 option:selected').val() + "'}",
                    success: function (result) {
                        var str3;
                        for (var i = 0; i < result.d.length; i++) {
                            str3 += "<option value=" + result.d.areaid + ">";
                            str3 += result.d[i].areaname;
                            str3 += result.d[i].father;

                        }
                        $('#select3').append(str3);
                    }
                })
            })
        })

    </script>
</head>
<body>
   省：
    <select id="select1">
        <option>--请选择--</option>
    </select>
    市：
    <select id="select2">
        <option>--请选择--</option>
    </select>
    县：
    <select id="select3">
        <option>--请选择--</option>
    </select>
</body>
</html>

[webmethod]//加载省
        public list<model.province> loadprovince()//为什么要用list因为这里出从前的值不可能一个实例是多个model实例，一个实例就是一条记载这样做防止字段错误
        {
            bll.province bp = new bll.province();
            list<model.province> list=bp.getlistmodel();
            return list;
        }
        [webmethod]//加载市
        public list<model.city> loadcity(string fatherid)
        {
            bll.city bc = new bll.city();
            list<model.city> list = bc.getlistmodel(fatherid);
            return list;
        }
        [webmethod]//加载县
        public list<model.area> loadarea(string fatherid)
        {
            bll.area ba = new bll.area();
            list<model.area> list = ba.getlistmodel(fatherid);
            return list;

        }
    }
}

public system.collections.generic.list<model.area> getlistmodel(string fatherid)
        {
            system.collections.generic.list<model.area> list = new system.collections.generic.list<model.area>();
            datatable dt = getlist("father=" + fatherid + "").tables[0];
            foreach (datarow row in dt.rows)
            {
                model.area ma = new model.area();
                ma.areaid = row["areaid"].tostring();
                ma.areaname = row["areaname"].tostring();
                ma.father = row["father"].tostring();
                list.add(ma);
            }
            return list;
        }

public system.collections.generic.list<model.area> getlistmodel(string fatherid)
        {
            system.collections.generic.list<model.area> list = new system.collections.generic.list<model.area>();
            datatable dt = getlist("father=" + fatherid + "").tables[0];
            foreach (datarow row in dt.rows)
            {
                model.area ma = new model.area();
                ma.areaid = row["areaid"].tostring();
                ma.areaname = row["areaname"].tostring();
                ma.father = row["father"].tostring();
                list.add(ma);
            }
            return list;
        }
    }

public system.collections.generic.list<model.province> getlistmodel()
        {
            //将要查的内容以实例的方式返回
            //这里要做的就是要建立list并将list用model实例填满，而model要用一个方法失掉数据并添加到model中
          //建list实例
            system.collections.generic.list<model.province> list = new system.collections.generic.list<model.province>();
            //已经有了的失掉数据的方法就不用自己写了通过调用getlist的方法操纵数据库拿到数据
            datatable dt = getlist("").tables[0];
            //拿到数据后就需要将数据添加到model实例中了

            foreach (datarow row in dt.rows)
            {
                //每一行都是个实例所以要将model的放在循环里面
                model.province mp = new model.province();
                mp.provinceid = row["provinceid"].tostring();
                mp.provincename = row["provincename"].tostring();
                list.add(mp);//没添加完一个实例都要放到list中
            }
            return list;

}

ajax.net +jquery 无刷新三级联动的实例代码