html >
head>
  title>/title>
  script src="js/Jquery1.7.js" type="text/javascript">/script>
  script type="text/javascript">
    $(function () {


      $('#Button1').click(function () {
        var username = $('#txtUserName').val();
        var pwd = $('#txtPwd').val();
        $.ajax({
          type: "post",
          contentType: "application/json",
          url: "WebService1.asmx/Login",
          data: "{username:'" + username + "',pwd:'" + pwd + "'}",
          success: function (bukeyi) {
            if (bukeyi.d == 'true') {
              window.location = 'HTMLPage1.htm';
            }
            else {
              $('#divinfo').text("用户名或密码错误");
            }
          }
        })
      })
    })
  /script>
/head>
body>
用户名input id="txtUserName" type="text" />br />
密码input id="txtPwd" type="text" />br />
  input id="Button1" type="button" value="登录" />br />
  div id="divinfo">/div>
/body>
/html>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;


namespace ajax11
{
  /// summary>
  /// WebService1 的摘要说明
  /// /summary>
  [WebService(Namespace = "http://tempuri.org/")]
  [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
  [System.ComponentModel.ToolboxItem(false)]
  // 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消对下行的注释。
  [System.Web.Script.Services.ScriptService]
  public class WebService1 : System.Web.Services.WebService
  {


    [WebMethod]
    public string HelloWorld()
    {
      return "Hello World";
    }
    [WebMethod]
    public string ValidateUser(string username)
    {
      if (username == "onlifes")
      {
        return "用户名已被占用，请选择其他";
      }
      else
      {
        return "可以使用，请继续";
      }
    }


    [WebMethod]
    public string GetDate()
    {
      return DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss");
    }
    [WebMethod]
    public string Login(string username, string pwd)
    {
      if (username == "admin"  pwd == "888888")
      {
        return "true";
      }
      else
      { return "false"; }


    }
  }
}