Untitled

<?php
$nomError = '';
$prenomError = '';
$emailError = '';
$phoneError = '';
$listeError = '';
$messageError = '';

if (isset($_POST['isFormSubmitted']))
{
    $nom = $_POST['nom'];
    $prenom = $_POST['prenom'];
    $email = $_POST['email'];
    $phone = $_POST['phone'];
    $liste = $_POST['liste'];
    $message = $_POST['message'];

    if (empty($nom) === true)
    {
        $nomError = '<br> Erreur : champ invalide';
    }

    if (empty($prenom) === true)
    {
        $prenomError = '<br> Erreur : champ invalide';
    }

    if (empty($email) === true)
    {
        $prenomError = '<br> Erreur : champ invalide';
    }

    if (empty($phone) === true)
    {
        $phoneError = '<br> Erreur : champ invalide';
    }

    if (empty($liste) === true)
    {
        $listeError = '<br> Erreur : champ invalide';
    }

    if (empty($message) === true)
    {
        $messageError = '<br> Erreur : champ invalide';
    }

    $variable = filter_var( $email,FILTER_VALIDATE_EMAIL);

    if ($variable === false)
    {
        $emailError = 'Mauvais email';
    }

    if (
        empty($nomError) && empty($prenomError) && empty($emailError) &&
        empty($listeErrorError) && empty($messageErrorError) && empty($phoneErrorError)
    )
    {
        header("Location: index.php");
    }
}

?>

<!DOCTYPE html>
<html lang="fr">
<head>
    <meta charset="UTF-8">
    <title>Label PHP</title>
    <meta name="">
</head>
<body>
    <form  action="form.php"  method="post">
        <p>
            <label  for="nom">Nom :*</label>
            <input  type="text"  id="nom"  name="nom">
        </p>
        <?php echo $nomError ?>
        <p>
            <label  for="prenom">Prénom :*</label>
            <input  type="text"  id="prenom"  name="prenom">
        </p>
        <?php echo $prenomError ?>
        <p>
            <label  for="email">e-mail :*</label>
            <input  type="text"  id="email"  name="email">
        </p>
        <?php echo $emailError ?>
        <p>
            <label for="phone">Enter your phone number:*</label>

            <input  type="tel" id="phone" name="phone">
        </p>
        <?php echo $phoneError ?>
        <p>
            <label for="liste">Choose an option:*</label>

            <select id="liste" name="liste">
                <option value=""> Please choose an option </option>
                <option value="option1">Option 1</option>
                <option value="option2">Option 2</option>
            </select>
        </p>
        <?php echo $listeError ?>
        <p>
            <label  for="message">Message :*</label>
            <textarea  id="message"  name="message"></textarea>
        </p>
        <?php echo $messageError ?>
        <div  class="button">
            <button  type="submit"name="isFormSubmitted">Envoyer votre message
            </button>
        </div>
    </form>
</body>
</html>