php loggedin()给出了错误的标题

Question

我是php的新手，所以我遵循WellBro的教程。我正在进行注册和登录。但是我的代码中有一个错误，它总是给出错误的标题。登录后，我需要看到“主页，专业人员和注销”，但我一直看到“主页，登录和注册”。所以我认为我的loggedin()有一个错误。谁能帮帮我？:)

登录的一部分

<?php
if (loggedin()) {
?>
<a href='index.php'>Home</a>
<a href='profile.php'>Profiel</a>
<a href='logout.php'>Log Out</a>
<?php
}else{  
?>
<a href='index.php'>Home</a>
<a href='login.php'>Log in</a>
<a href='register.php'>Registreer</a>
<?php
}
>

<?php
if(isset($_POST['submit'])){
$username = $_POST['username'];
$password = md5($_POST['password']);
if(empty($username) or empty ($password)){
    echo"<p>Gelieve al de velden in te vullen.</p>";
    }else{
        $check_login = mysql_query("SELECT id, type FROM users WHERE username='$username' AND password = '$password'");
            if (mysql_num_rows($check_login)==1){
                $run = mysql_fetch_array($check_login);
                $user_id=$run['id'];
                $type = $run ['type'];
                if($type == 'd'){
                    echo "<p>Je account is nog niet geactiveerd. Je ontvangt een mail zodra dit in orde is. Als je na lange tijd nog steeds niet kunt inloggen, neem dan contact op met één van de trainers.</p>";
                    }else{
                        $_SESSION['user_id'] = $user_id;
                        echo "<script> window.location.replace('membersonly.php') </script>";
                        }
                }else{
                    echo "<p>Ongeldige gebruikersnaam of wachtwoord.</p>";
                    }
        }
}
?>

function.php

<?php

session_start();

function loggedin() {
    if(isset($_SESSION['user_id']) && !empty($_SESSION['user_id'])) {
        return true;
    }else{
        return false;
    }
}

?>

membersonly.php的一部分

<?php include 'connect.php'; ?>

<?php include 'functions.php'; ?>

<?php

if (loggedin()) {
?>
<a href='index.php'>Home</a>
<a href='profile.php'>Profiel</a>
<a href='logout.php'>Log Out</a>
<?php
}else{  
?>
<a href='index.php'>Home</a>
<a href='login.php'>Log in</a>
<a href='register.php'>Registreer</a>
<?php
}
?>

Answer 1

我看不到你的表格，但你应该有这样的表格。

<form action='PartOfLogin.php' method='POST'>
Gebruikersnaam: <br/> 
<input type= 'text' name='username' /> 
<br/>
<br/> 

Wachtwoord: 
<br/> 
<input type= 'password' name ='password' /> 
<br/>
<br/> 

<input type='submit' name='submit' value='Login' />
</form>

登录的一部分。同时将php中的“or”更改为"||“

<?php
if(isset($_POST['submit'])){
$username = $_POST['username'];
$password = md5($_POST['password']);
if(empty($username) || empty ($password)){
    echo"<p>Gelieve al de velden in te vullen.</p>";
    }else{
        $check_login = mysql_query("SELECT id, type FROM users WHERE username='$username' AND password = '$password'");
            if (mysql_num_rows($check_login)==1){
                $run = mysql_fetch_array($check_login);
                $user_id=$run['id'];
                $type = $run ['type'];
                if($type == 'd'){
                    echo "<p>Je account is nog niet geactiveerd. Je ontvangt een mail zodra dit in orde is. Als je na lange tijd nog steeds niet kunt inloggen, neem dan contact op met één van de trainers.</p>";
                    }else{
                        $_SESSION['user_id'] = $user_id;
                        echo "<script> window.location.replace('membersonly.php') </script>";
                        }
                }else{
                    echo "<p>Ongeldige gebruikersnaam of wachtwoord.</p>";
                    }
        }
}
if (loggedin()) {
?>
<a href='index.php'>Home</a>
<a href='profile.php'>Profiel</a>
<a href='logout.php'>Log Out</a>
<?php
}else{  
?>
<a href='index.php'>Home</a>
<a href='login.php'>Log in</a>
<a href='register.php'>Registreer</a>
<?php
}
>

并将mysql函数更改为mysli函数。

参考：http://www.w3schools.com/php/php_mysql_intro.asp