我有一个登录系统，其中有多个成员类型。我需要这段代码在找不到已输入的电子邮件和密码时显示错误消息。
换句话说，当输入错误的登录详细信息时，我需要它来显示错误消息。目前，当输入错误的详细信息时，页面会刷新。
$check_user = mysqli_num_rows($user_query); // checking to see if there is infact a user which those credentials in the DB
if ($check_user==1){
while ($row = mysqli_fetch_array($user_query)){
$id = $row['user_id'];
$user_type = $row['account'];
}
$_SESSION["user_login"] = $login_user;
// check the user type and redirect according to it
if($user_type == "Student"){
$student_page = "profile_student.php";
header( "Location:{$student_page}" );
} elseif ($user_type == "Landlord"){
$landlord_page = "landlord_profile.php";
header( "Location:{$landlord_page}" );
} elseif ($user_type == "Administrator"){
$admin_page = "admin_profile.php";
header( "Location:{$admin_page}" );
}else {
$refresh_page = "sign_up.php";
}
header( "Location:{$refresh_page}" ); // refresh page
exit;
}else {
echo "<div class='wrong_login'>
<p> Email or password is incorrect, please try again. </p>
</div>";
}
}
?>
在标头之后，必须使用"exit（）";否则代码执行将继续。
代码执行继续到最后一个重定向标头，这就是接下来的内容。
已修复，代码更易于阅读：
if($user_type == "Student"){
$refresh_page = "profile_student.php";
} elseif ($user_type == "Landlord"){
$refresh_page = "landlord_profile.php";
} elseif ($user_type == "Administrator"){
$refresh_page = "admin_profile.php";
}else {
$refresh_page = "sign_up.php";
}
header( "Location:{$refresh_page}" ); // refresh page
exit;
或做
if($user_type == "Student"){
$student_page = "profile_student.php";
header( "Location:{$student_page}" );
exit();
} elseif ($user_type == "Landlord"){
$landlord_page = "landlord_profile.php";
header( "Location:{$landlord_page}" );
exit();
} elseif ($user_type == "Administrator"){
...