在基于php的系统中，如何在同一页面上显示登录错误消息？

Question

I am building a php based login system where the user is required to put in a username and password for logging in. My question is 'how can I display the 'invalid username or password' error message on the same page'? 我正在构建一个基于php的登录系统，需要用户输入用户名和密码才能登录。我的问题是“如何在同一页面上显示“无效的用户名或密码”错误消息”？ I have tried many things including trying to use a query string (/?error=1); 我尝试了很多事情，包括尝试使用查询字符串（/？error = 1）； it did solve my problem by displaying the error message on the same page but all the CSS was just gone from the page and I couldn't find a way to fix it (not for the lack of trying, though). 它确实通过在同一页面上显示错误消息解决了我的问题，但是所有CSS都刚刚从页面上消失了，我找不到解决它的方法（尽管如此，这不是缺乏尝试）。 So I decided to try a simpler method which, obviously, did not work. 因此，我决定尝试一种更简单的方法，该方法显然行不通。 So, how can I fix it? 那么，我该如何解决呢？ Here's my PHP code: 这是我的PHP代码：

<?php
session_start();
$db = mysqli_connect("localhost","root","","combination");
if(isset($_POST['login_btn'])){

    $username = mysql_real_escape_string($_POST['username']);
    $password = mysql_real_escape_string($_POST['password']);

    $password=md5($password);
    $sqlquery="SELECT * FROM registration WHERE username='$username' AND password='$password'";
    $result = mysqli_query($db,$sqlquery);


    if(mysqli_num_rows($result)==1){

        $_SESSION['message']="You are now logged in.";
        $_SESSION['username'] = $username;
        $_SESSION['password'] = $password;

        header("location:loginhome.php");
    }
    else{
        $_SESSION['message']="Incorrect Username or Password."; 
        header("location:login.php");
        echo '<h3>Invalid username or password</h3>';
    }

}
?>

Answer 1

Here is a simple example to help you. 这是一个简单的示例，可以为您提供帮助。 You need to use $_SESSION variables. 您需要使用$_SESSION变量。

login.php: login.php：

<?php
session_start();
?>

<!DOCTYPE html>

<html>

    <head>
        <title>Login</title>
        <link rel="stylesheet" type="text/css" href="style.css">
    </head>

    <body>
        <form action="check.php" method="POST">
            <input type="text" class="input" name="username" placeholder="username">
            <input  type="password" class="input" name="pass" placeholder="pass">
            <input class="button" type="submit" id="login" name="login" value="login">  
                <?php
                    if(isset($_SESSION["error"])){
                        $error = $_SESSION["error"];
                        echo "<span>$error</span>";
                    }
                ?>  
        </form>
    </body>
</html>

<?php
    unset($_SESSION["error"]);
?>

check.php: check.php：

<?php

session_start();

$username = $_POST["username"];
$error = "username/password incorrect";

if($username == "admin"){
    $_SESSION["username"] = $username;
    header("location: homepage.php"); //send user to homepage, for example.
}else{
    $_SESSION["error"] = $error;
    header("location: login.php"); //send user back to the login page.
}

?>

在基于php的系统中，如何在同一页面上显示登录错误消息？

问题描述

1 个解决方案

解决方案1
4 已采纳 2017-03-13 15:15:20

在基于php的系统中，如何在同一页面上显示登录错误消息？

问题描述

1 个解决方案

解决方案1 4 已采纳 2017-03-13 15:15:20

解决方案1
4 已采纳 2017-03-13 15:15:20