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  PHP 登录示例

  • 登录页面

    登录页面应如下所示，并根据会话工作。如果用户关闭会话，它将擦除会话数据。

    登录界面login.php

    <?php
ob_start();
session_start();
?>

<?
// error_reporting(E_ALL);
// ini_set("display_errors", 1);
?>

<html lang = "en" >

<head>
        <title>jc2182.com</title>
        <link href = "bootstrap.min.css" rel = "stylesheet">

        <style>
                body {
                        padding-top: 40px;
                        padding-bottom: 40px;
                        background-color: #ADABAB;
                }

                .form-signin {
                        max-width: 330px;
                        padding: 15px;
                        margin: 0 auto;
                        color: #017572;
                }

                .form-signin .form-signin-heading,
                .form-signin .checkbox {
                        margin-bottom: 10px;
                }

                .form-signin .checkbox {
                        font-weight: normal;
                }

                .form-signin .form-control {
                        position: relative;
                        height: auto;
                        -webkit-box-sizing: border-box;
                        -moz-box-sizing: border-box;
                        box-sizing: border-box;
                        padding: 10px;
                        font-size: 16px;
                }

                .form-signin .form-control:focus {
                        z-index: 2;
                }

                .form-signin input[type="email"] {
                        margin-bottom: -1px;
                        border-bottom-right-radius: 0;
                        border-bottom-left-radius: 0;
                        border-color:#017572;
                }

                .form-signin input[type="password"] {
                        margin-bottom: 10px;
                        border-top-left-radius: 0;
                        border-top-right-radius: 0;
                        border-color:#017572;
                }

                h2{
                        text-align: center;
                        color: #017572;
                }
        </style>

</head>

<body>

<h2>输入用户名和密码</h2>
<div class = "container form-signin">

        <?php
        $msg = '';

        if (isset($_POST['login']) && !empty($_POST['username']) && !empty($_POST['password'])) {

                if ($_POST['username'] == 'jc2182' && $_POST['password'] == '123456') {
                        $_SESSION['valid'] = true;
                        $_SESSION['timeout'] = time()+ 2400;  // 一个小时过期
                        $_SESSION['username'] = $_POST['username'];

                        echo '您输入了有效的用户名和密码';

                        // 两秒后跳转到 welcome.php
                        header('Refresh: 2; URL = welcome.php');
                }else {
                        $msg = '错误的用户名或密码';
                }
        }
        ?>
</div> <!-- /container -->

<div class = "container">

        <form class = "form-signin" role = "form"  action = "<?php echo htmlspecialchars($_SERVER['PHP_SELF']);  ?>" method = "post">
                <h4 class = "form-signin-heading"><?php echo $msg; ?></h4>
                <input type = "text" class = "form-control"  name = "username" placeholder = "username = jc2182" required autofocus></br>
                <input type = "password" class = "form-control"  name = "password" placeholder = "password = 123456" required>
                <button class = "btn btn-lg btn-primary btn-block" type = "submit"  name = "login">登录</button>
        </form>


</div>

</body>
</html>
    上面的代码加载了一个样式文件bootstrap.min.css，是前端界面框架bootstrap的样式文件，下载地址：》》》》》》》》

    登录成功页面：welcome.php

    <html lang = "en" >
<?php
session_start();
if (isset($_SESSION["username"]) && $_SESSION['valid'] == true){  // 登录成功的
        echo '欢迎您:::<span style="color: green">'.$_SESSION['username'].'</span><br/>';
?>
        点击这里<a href = "logout.php" tite = "退出登录">退出登录.</a>
<?php
}else{ //未经登录直接访问这个页面的
        echo '请您先登录<br/>';
        // 两秒后跳转到 login.php
        header('Refresh: 2; URL = login.php');
}
?>
</html>

    退出登录页面：logout.php

    <?php
session_start();
unset($_SESSION["username"]);
unset($_SESSION["password"]);
unset($_SESSION['valid']);

echo '您清除了会话';
// 两秒后跳转到 login.php
header('Refresh: 2; URL = login.php');
?>
    提示：一般用户信息都保存在数据库，登录的时候回跟数据库的数据校检，还用用PHP进行一些必要的防SQL注入处理。
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