jQuery+JSON实现AJAX二级联动实例分析

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

<%@ 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

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>dropdownlit </title>
<meta name="Generator" content="EditPlus" />
<script type="text/javascript" src="js/jQuery-1.5.2.js"></script>
<script type="text/JavaScript">
 $(function(){
   InitData(0);
 });
 function InitData(n)
 {
   $.ajax({
   type:"post",
   dataType:"json",
   url: "Handler.ashx",
   data:{"n":n},
   success:function(json){
    $.each(json,function(i,n){
     var pro=$("#dl1");
     $(""+ n.A_Name +"").appendTo(pro);
    });
   }
  });
 }
 function GetCity(n)
 {
  var city=$("#dl2");
  city.html("");
   $.ajax({
   type:"POST",
   dataType:"json",
    url: "Handler.ashx",
   data:{"n":n},
   success:function(json){
    $.each(json,function(i,n){
     $(""+ n.A_Num1 +">"+ n.A_Name +"").APPendTo(city);
    });
   }
  });
 }
</script>
</head>
<body>
 <select id="dl1" onchange="GetCity(this.value)">
 </select>
 <select id="dl2">
 </select>
</body>
</html>