Odtnhj

my code is ...

<?php
 $username = mysql_real_escape_string($_POST['username']);
 $password = mysql_real_escape_string($_POST['password']);
 $passwordr = mysql_real_escape_string($_POST['passwordr']);
 $email = mysql_real_escape_string($_POST['email']);

 if(empty($username) || empty($password) || empty($passwordr) || empty($email)) 
 echo '<div class="alert alert-danger">Bitte fülle alle Felder aus.</div>';
 

 elseif(!preg_match('/^[a-zA-Z0-9-_^#]4,15$/', $username)) 
 echo '<div class="alert alert-danger">Bitte gebe einen gültigen Usernamen ein.<br />Der Username muss mindestens 4 und maximal 15 Zeichen lang sein und darf nur folgende Sonderzeichen enthalten: -_^#</div>';
 

 elseif(!preg_match('/^[a-zA-Z0-9-_*^#?!.,;@€]8,20$/', $password)) 
 echo '<div class="alert alert-danger">Bitte gebe ein gültiges Passwort ein.<br />Das Passwort muss mindestens 8 und maximal 20 Zeichen lang sein und darf nur folgende Sonderzeichen enthalten: -_*^#?!.,;@€</div>';
 

 elseif($passwordr != $password) 
 echo '<div class="alert alert-danger">Die Passwörter stimmen nicht überein.</div>';
 

 elseif(!preg_match('/^[a-zA-Z0-9-_.]+@[a-zA-Z0-9-_.]+.[a-zA-Z]2,4$/', $email)) 
 echo '<div class="alert alert-danger">Bitte gebe eine gültige E-Mail Adresse ein.</div>';
 

 else 
 die("have a n1 day");
 
 ?>

somehow, I always get <div class="alert alert-danger">Bitte fülle alle Felder aus.</div>, even when the forms aren't empty.

why?

here's my form ...

<div class="row">
 <form method="POST">
 <fieldset>
 <div class="col-lg-5">
 <div id="username-group" class="form-group">
 <label for="username">Username</label>
 <input type="text" name="username" id="username" class="form-control" placeholder="Username">
 </div>
 <div id="password-group" class="form-group">
 <label for="password">Passwort</label>
 <input type="password" name="password" id="password" class="form-control" placeholder="Passwort">
 </div>
 <div id="passwordr-group" class="form-group">
 <label for="passwordr">Passwort wiederholen</label>
 <input type="password" name="passwordr" id="passwordr" class="form-control" placeholder="Passwort wiederholen">
 </div>
 <div id="email-group" class="form-group">
 <label for="email">E-Mail</label>
 <input type="email" name="email" id="email" class="form-control" placeholder="E-Mail">
 </div>
 <input type="submit" name="submit" id="submit" class="btn btn-default" value="Registrieren">
 </div>
 </fieldset>
 </form>
 </div>

I'm using bootstrap, but I don't think that's the problem.
and the code looks fine too.

If you add the error logging

error_reporting(E_ALL);
ini_set('display_errors','On');

you will see this:

Deprecated: mysql_real_escape_string(): The mysql extension is
deprecated and will be removed in the future: use mysqli or PDO
instead in .../public_html/index.php on line 38

Warning: mysql_real_escape_string(): Access denied for user 'www-data'@'localhost' (using password: NO) in
.../public_html/index.php on line 38

mysql_real_escape_string requires you to connect to the database first. Also indeed this function is deprecated.

You can start with deleting mysql_real_escape_string from the code to see that it works.