jquery ajax

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="index1.aspx.cs" Inherits="index1" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>从另一个页面加载数据到当前页面</title>
    <script src="js/jquery-3.2.1.min.js"></script>
    <script type="text/javascript">
        $(function () {
            $("#btn").click(function () {
                $("#box").load("test.ashx"); //load()方法法
                //将test.ashx页面的数据加载到id 为box的元素中,如果只需要加载test.ashx页面某个元素的内容,例如加载<p>标记的内容,则可写为:
                //$("#box").load("test.ashx p").
            });
        })
    </script>
    <script type="text/javascript">
        $(function () {
            $("#btnLogin").click(function () {
                $("#box2").load("test.ashx", { "txtName": " admin", "txtPwd": "pwd" }); //load() 方法

            });

        })
    </script>
    <script type="text/javascript">
        $(function () {
            $("#Getbtn").click(function () { //data(发送的key/value 或json风格的字符串作为数据格式)
                $.get("test.ashx", { "txtName": " admin", "txtPwd": "pwd" }, function (data) {
                    if (data == "ok") {
                        alert("main.aspx");
                    } else {
                        alert(data);
                    }
                });
            });
        })
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <div id="box">
            <input type="button" id="btn" value="加载数据" />
        </div>
        <div id="box2">
            <input type="button" id="btnLogin" value="登录" />
        </div>
        <div id="box3">
            <input type="button" id="Getbtn" value="GET" />
        </div>
    </form>
</body>
</html>
一般处理程序 
context.Response.ContentType = "text/plain"; string ss = context.Request["txtName"]; context.Response.Write(ss); context.Response.Write("Hello World");