本文实例讲述了jQuery+JSON实现AJAX二级联动的方法。分享给大家供大家参考，具体如下：
后台Handler.ashx
using System;
using System.Web;
using System.Data;
public class Handler : IHttpHandler
{
Common coObj = new Common();
public void ProcessRequest(HttpContext context)
{
if (context.Request.Params["n"] != null)
{
string num = context.Request.Params["n"].ToString();
context.Response.ContentType = "text/plain";
string str = "select * from address where a_num2=" + num;
DataTable dt = coObj.GetTable(str);
string json = JSONHelper.DataTableToJSON(dt);
context.Response.Write(json);
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
前台dropdownlist.html