Question

我尝试使用php创建登录页面，我希望我的代码检查按下登录按钮后给出的用户名和密码。但即使没有按下登录按钮，代码也会执行。我在线搜索了几十个代码，几乎所有这些代码都以这种方式实现，所以我无法理解这里的错误。这是我的代码：

<HTML>
    <HEAD>
        <TITLE>Welcome to FoodOrder - Log In or Sign Up</TITLE>

    </HEAD>
    <BODY background = "foodOrder.png">

        <?php
        session_start();
        $con = mysqli_connect("xxxx", "xxxx", "xxxx", "xxxx");

        if(mysqli_connect_errno()){
            echo "Failed to connect, please check your username and password: ".mysqli_connect_error();
        }

        if(isset($_SESSION['user'])!= ""){
            header("Location: home.php");
        } 

        if(isset($_POST["login_button"])){
            $username = mysqli_real_escape_string($_POST['username']);
            $password = mysqli_real_escape_string($_POST['password']);
            $sql = "SELECT password from user where username  = '$username'";
            $res = mysqli_query($con,$sql);
            $row = mysqli_fetch_array($res);
            if($row['password'] == md5($password)){
                $_SESSION['user'] = $username;
                header("Location : home.php");
            } else {
                ?> <script>alert('wrong username or password');</script> <?php
            }
        }


        ?>

        <center>
            <div id ="login form">
                <form  method = "POST">
                    <table align = "center" width = "25%" border = "0">
                        <tr>
                            <td><input type = "text" name = "username" placeholder = "your_username_here" required></td>
                        </tr>
                        <tr>
                            <td><input type = "text" name = "password" placeholder = "your_password_here"></td>
                        </tr>
                        <tr>
                            <td><input type = "submit" name = "login_button"  value = "Log In" /></td>
                        </tr>
                        <tr>
                            <td><a href = "register.php">Sign Up</a></td>
                        </tr>
                    </table>
                </form>
            </div>
        </center>

    </BODY>



</HTML>

Answer 1

删除md5一次，检查您的代码。 $_SESSION VARIABLE无法正常工作。

也尝试替换此

 if(isset($_SESSION['user'])!= ""){
            header("Location: home.php");
        }

用这个

if(!$_SESSION['user']){
            header("Location: home.php");
        }

php isset无法使用提交按钮

1 个答案: