Pourquoi les données de mon formulaire sérialisé jQuery n'atteignent-elles pas le serveur PHP ?

<code class="html"><form id="contactForm" name="contactForm" method="post">
    <input type="text" name="nume" size="40" placeholder="Nume">
    <input type="text" name="telefon" size="40" placeholder="Telefon">
    <input type="text" name="email" size="40" placeholder="Email">
    <textarea name="comentarii" cols="36" rows="5" placeholder="Message"></textarea>
    <input id="submitBtn" type="submit" name="submit" value="Trimite">
</form></code>

<code class="javascript">$("#contactForm").submit(function(e) {
    e.preventDefault(); // Prevent browser submission
    $.post("getcontact.php", $("#contactForm").serialize())
    .done(function(data) {
        // Process server response
    });
});</code>

<code class="php">$nume = $_POST["nume"];
$email = $_POST["email"];
$telefon = $_POST["telefon"];
$comentarii = $_POST["comentarii"];</code>

<code class="javascript">$.ajax({
    type: "POST",
    url: "getcontact.php",
    data: $("#contactForm").serialize(),
    dataType: "json",
    success: function(data) {
        // Process server response
    },
    error: function() {
        // Handle errors
    }
});</code>