AJAX下拉框联动

 function getProvince() {
     var ProName = $("#dvProv").val();
     LoadProvince(ProName);
 }
 function getCity() {
     var CityName = $("#dvCity").val();
     LoadBus(CityName);
 }
 function getArea() {
     var AreaName = $("#dvDealer").val();
     LoadAdd(AreaName);

 }
 //查询市
 function LoadProvince(proname) {

     $.ajax({
         type: "post",
         dataType: "json",
         url: "/ashx/Province.ashx",
         data: {
             proName: proname,
         },
         success: function (data) {
             var table = data.data.Rows;
             var contentcity = "";
             if (table.length > 0) {
                 contentcity += "<option value=\"\">请选择市</option>  ";
                 for (var i = 0; i < table.length; i++) {
                     contentcity += "<option value=\"" + table[i]["city"] + "\" >" + table[i]["city"] + "</option>  ";
                 }
                 $("#dvCity").html(contentcity);

             }

         },
         error: function () {
             alert("ajax error");
         }
     });
 }
 //查询经销商

 function LoadBus(cityname) {

     $.ajax({
         type: "post",
         dataType: "json",
         url: "/ashx/Dealer.ashx",
         data: {
             cityName: cityname,
         },
         success: function (data) {
             var table = data.data.Rows;
             var contentDealer = "";
             if (table.length > 0) {
                 contentDealer += "<option value=\"\">请选择经销商</option>  ";
                 for (var i = 0; i < table.length; i++) {
                     contentDealer += "<option value=\"" + table[i]["DealersName"] + "\" >" + table[i]["DealersName"] + "</option>  ";
                 }
                 $("#dvDealer").html(contentDealer);

             }

         },
         error: function () {
             alert("ajax error");
         }
     });
 }

 //经销商地址

 function LoadAdd(deaname) {

     $.ajax({
         type: "post",
         dataType: "json",
         url: "/ashx/BusAdd.ashx",
         data: {
             deaName: deaname
         },
         success: function (data) {
             var table = data.data.Rows;
             var contentadd = "";
             if (table.length > 0) {

                 for (var i = 0; i < table.length; i++) {
                     contentadd = table[i]["location"];
                 }

                 $("#dvAddr1").val(contentadd);
                 $("#dvAddr").html(contentadd);

             }

         },
         error: function () {
             alert("ajax error");
         }
     });
 }

<%@ WebHandler Language="C#" Class="Province" %>

using System.Web;
using Maticsoft.DBUtility;
using System.Data;
using System.Data.SqlClient;
using MT.Business;
using Solucky;

public class Province : IHttpHandler {

    protected string proName = "";

    public void ProcessRequest (HttpContext context)
    {
        context.Response.ContentType = "application/json";
        proName =PageValidate.SqlTextClear(context.Request["proName"]);
        try
        {
            string str= GetCitycode(context);
            context.Response.Write("{\"data\":" + str + "}");
        }

        catch (System.Exception ex)
        {
            throw;
        }

    }

    /// <summary>
    /// 查询城市
    /// </summary>
    public string GetCitycode(HttpContext context)
    {
        string result = "";

        string sql = "SELECT DISTINCT city,Citycode FROM B_Dealer where province=@proName";
        SqlParameter[] sqlParams = {
            new SqlParameter("@proName",SqlDbType.NVarChar,),
            };
        sqlParams[].Value = proName;
        DataTable dt = DbHelperSQL.Query(sql, sqlParams).Tables[];
        Json json = new Json();
        string  dtdata = json.Convert2Json(dt);
        return dtdata;
    }

    public bool IsReusable
    {
        get {
            return false;
        }
    }

}

<div class="row">
                                <div class="form-group col-xs-6">
                                    <label class="control-label"><i class="must">*</i>经销商省市</label>
                                    <div class="form-group-bd">
                                        <div class="frm-choose-area">
                                            <div class="frm-col-box col-xs-6">
                                                <select class="form-control" name="dvProv" id="dvProv" onchange="getProvince()">
                                                    <option value="">请选择省</option>
                                                    <asp:Repeater ID="repProvince" runat="server">
                                                        <ItemTemplate>
                                                            <option value="<%#Eval("province")%>"><%#Eval("province")%></option>
                                                        </ItemTemplate>
                                                    </asp:Repeater>
                                                </select>
                                            </div>
                                            <div class="frm-col-box col-xs-6">
                                                <select class="form-control" name="dvCity" id="dvCity" onchange="getCity()">
                                                    <option value="">请选择市</option>
                                                </select>
                                            </div>
                                        </div>
                                    </div>
                                </div>

                                <div class="form-group col-xs-6">
                                    <label class="control-label" for="dvDealer"><i class="must">*</i>经销商选择</label>
                                    <div class="form-group-bd">
                                        <select class="form-control" name="dvDealer" id="dvDealer" onchange="getArea()">
                                            <option value="">请选择经销商</option>
                                        </select>
                                    </div>
                                </div>
                            </div>

                            <div class="row">
                                <div class="form-group frm-dvAddr-box">
                                    <label class="control-label">经销商地址</label>
                                    <div class="form-group-bd">
                                        <div class="form-control" id="dvAddr"></div>
                                        <input type="hidden" name="dvAddr1" id="dvAddr1" class="form-control">
                                    </div>
                                </div>
                            </div>