实现用户注册，要求输入用户名之后，焦点离开判断用户名是否存在，如果存在给出提示，不存在允许注册改用户。要求使用AJAX 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace AJAX
{
    /// <summary>
    /// LoginHandler 的摘要说明
    /// </summary>
    public class LoginHandler : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";

            string UserName = context.Request["UserName"];

            string UserPwd = context.Request["UserPwd"];
            if (string.IsNullOrEmpty(UserName))
            {
                context.Response.Redirect("Login.html");
            }
            string sql = "select count(*) from Users where UserName=@u ";
            SqlParameter[] p = { new SqlParameter("@u",UserName)};
            int i = Convert.ToInt32(SQLHelper.ExecuteScalar(sql,p));
            if (i==1)
            {
                context.Response.Write("1");
            }
            else
            {
                string s = "insert into Users (UserName,Pwd) values (@UserName,@p)";
                SqlParameter[] sp = { new SqlParameter("@UserName",UserName),
                                      new SqlParameter("@p",UserPwd)};
                int j = Convert.ToInt32(SQLHelper.NonExQuery(s, sp));
                if (j == 1)
                {
                    context.Response.Write("0");
                }
            }
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title></title>
    <meta charset="utf-8" />
    <script src="js/jquery-3.3.1.js"></script>    
    <script>
        $(function () {
            $("#UserName").blur(function () {
                var UserName = $("#UserName").val();                
                $.post("LoginHandler.ashx", { "UserName": UserName},function (data) {
                    if (data == "1") {
                        $('#btn').attr('disabled',"true");
                        alert("已经注册过了");
                    }
                    else {
                        $('#btn').removeAttr("disabled");
                    }
                });
            });
            $("#btn").click(function () {
                var UserName = $("#UserName").val();
                var UserPwd = $("#UserPwd").val();
                $.post("LoginHandler.ashx", {"UserName": UserName, "UserPwd": UserPwd }, function (data) {
                    if (data == "0") {
                        alert("注册成功！");
                    }
                })
            })
        });
    </script>
</head>
<body>
    用户名：<input type="text" name="UserName" id="UserName" />
    <br />
    密&nbsp;&nbsp;码：<input type="password" name="UserPwd" id="UserPwd" />
    <br />
    <input type="button" value="注册" id="btn" />
</body>
</html>

 

posted @ 2018-04-09 15:11  你的斗志并没有失去  阅读(1570)  评论(0)    收藏  举报