jqueryjsonajax二级联动菜单实例

后台Handler.ashx

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