<%@ Page Language="C#" AutoEventWireup="true" CodeFile="index.aspx.cs" Inherits="index" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>[Ajax测试]</title>
    <script type="text/javascript" src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $("button").click(function () {
                $.ajax({
                    type:"post",//Must be POST
                    contentType: "application/json",//Must
                    data:"{'name':'xtyang','age':23}",//Response to parameters of method getReturn
                    url: "index.aspx/getReturn",
                    success: function (result) {
                        alert(result.d);//Must
                    }
                });
            });
            $(".Input").blur(function () {
                $.ajax({
                    type: "POST",
                    url: "index.aspx/getCount",
                    contentType: "application/json",
                    data: "{'str':'" + $('.Input').val()+ "'}",//notice "'"
                    success: function (result) {
                        $('.ret-i').html("");//set the content with empty content
                        $('.ret-i').html(result.d);
                    }
                });
            });
        }
        );
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <button id="ajax">Test</button>
        <input type="text" class="Input" />
    </div>
    <div class="ret-i">
    </div>
    </form>
</body>
</html>
using System;
using System.Web.Services;  //Must

public partial class index : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        
    }
    [WebMethod]

    public static string getReturn(string name,int age)    //Must
    {
        return name + " is " + age.ToString() + " years old";
    }
    [WebMethod]
    public static string getCount(string str)
    {
        if (str.Length < 6)
            return "Input is not valid";
        else
            return "Input is valid";
    }
    
}