Verwijderen met checkboxes (Opgelost)

<?php

include_once('config.php');
if(isset($_POST['submit'])) {
$in = implode(', ', $_POST['check']);
$query = "DELETE FROM mail WHERE mail_id IN (".$in.")";  
mysql_query($query) or die (mysql_error());
echo "Het is gelukt";
} else {}

?>

<?php
 
include_once('config.php');
if(isset($_POST['submit'])) {
$in = implode(', ', $_POST['check']);
$query = "DELETE FROM mail WHERE mail_id IN (".$in.")";  
mysql_query($query) or die (mysql_error());
echo "Het is gelukt";
} else {}
 
?>

<form name="delete" action="" method="post">
  <input type="checkbox" name="check[]" value="<?php echo $rij_mail['mail_id']; ?>" />
<input type="submit" value="Verwijderen" id="submit" name="submit" />
</form>

<form name="delete" action="" method="post">
  <input type="checkbox" name="check[]" value="<?php echo $rij_mail['mail_id']; ?>" />
<input type="submit" value="Verwijderen" id="submit" name="submit" />
</form>