tchat ajax/php : les messages ne s'affichent pas automatiquement

Bonsoir,

J'ai utiliser le tuto Tchat Ajax/PHP pour faire un tchat privée ente deux utilisateurs tout fonctionne parfaitement sauf l'affichage automatique des messages. je vous met le code de mes trois pages :

tchat.php :

<?php
  include('includes/header.php');
?>
<div class="row">
  <div id="contentTchat" class="large-12 columns" role="content">
        <div id="conteneur">
            <p><i>Vous êtes connecté en tant que <?php echo $_SESSION"login"]; ?></i></p>
            <!-- <div id="connected">
            </div> -->
            <div id="tchat">
                <?php
                    if(isset($_POST'idUser']))
                        $_SESSION'idUser2'] = $_POST'idUser'];
                    $sql = "SELECT * FROM messages";
                    $sql .= " WHERE (idUser1 = ".$_SESSION'id']." AND idUser2 = ".$_SESSION'idUser2'].")";
                    $sql .= " OR (idUser1 = ".$_SESSION'idUser2']." AND idUser2 = ".$_SESSION'id'].")";
                    $sql .= " ORDER BY date DESC LIMIT 15";
                    $req = $dbh->query($sql) or die(print_r($dbh->errorInfo()));
                    $d = array();
                    while($data = $req->fetch(PDO::FETCH_ASSOC)){
                        $d] = $data;
                    }
                    for ($i=count($d)-1; $i >= 0 ; $i--)
                    {
                        $date_fr = date('d/m à H:i:s', $d$i]"date"]);
                    ?>
                        <p><strong class="NomUserTchat"><?php echo NomTchatUser($d$i]"idUser1"], $dbh); ?></strong> le <em><?php echo $date_fr; ?></em> : <?php echo htmlentities($d$i]"content"]); ?></p>
                    <?php
                    }
                ?>
            </div>
        </div>
        <div id="tchatForm" class="large-12 columns">
            <form method="POST" action="#" name="testForm">
                <div class="large-12 columns">
                    <textarea name="message" rows="5" cols="70"></textarea>
                </div>
                <div class="large-12 columns">
                    <input class="button postfix" type="submit" value="Envoyer">
                </div>
            </form>
        </div>
    </div>
</div>
<?php
  include('includes/footer.php');
?>

tchat.js :

var url = "tchatAjax.php";
var lastid = 0;
var timer = setInterval(getMessages,5000);
// var ctimer = setInterval(getConnected,10000);
$(function(){
    $("#tchatForm form").submit(function(){
        clearInterval(timer);
        var message = $("#tchatForm form textarea").val();
        $.post(url,{action:"addMessage", message:message},function(data){
            if (data.erreur == "ok") {
                getMessages();
                $("#tchatForm form textarea").val("");
            }
            else{
                alert(data.erreur);
            }
            timer = setInterval(getMessages,5000);
        },"json");
        return false;
    })
});
function getMessages(){
    $.post(url,{action:"getMessages", lastid:lastid},function(data){
            if (data.erreur == "ok") {
                $("#tchat").append(data.result);
                lastid = data.lastid;
            }
            else{
                alert(data.erreur);
            }
        },"json");
        return false;
}

tchatAjax.php :

<?php
  include('includes/header.php');
?>
<?php
$d = array();
if (!isset($_SESSION"login"]) || empty($_SESSION"login"]) || !isset($_POST"action"])) {
    $d"erreur"] = "Vous devez être connecté pour utiliser le tchat";
}
else{
    extract($_POST);
    $pseudo = $_SESSION"login"];
    /**
     * Action : addMessage
     * Permet l'ajout d'un message
     */
    if ($_POST"action"] == "addMessage") {
        $req = $dbh->prepare('INSERT INTO messages(id, content, idUser1, idUser2, date) VALUES (:id, :content, :idUser1, :idUser2, :date)');
        $req->bindParam(':id', $id);
        $req->bindParam(':content', $content);
        $req->bindParam(':idUser1', $idUser1);
        $req->bindParam(':idUser2', $idUser2);
        $req->bindParam(':date', $date);
        $id = '';
        $content = $_POST'message'];
        $idUser1 = $_SESSION'id'];
        $idUser2 = $_SESSION'idUser2'];
        $date = time();
        //Execution
        $req->execute();
        $d"erreur"] = "ok";
    }
    /**
     * Action : getMessages
     * Permet l'affichage des derniers messages
     */
    if ($_POST"action"] == "getMessages") {
        $lastid = floor($lastid);
        $sql = "SELECT * FROM messages WHERE id>$lastid ORDER BY date ASC";
        $req = $dbh->query($sql) or die(print_r($dbh->errorInfo()));
        $d"result"] = "";
        $d"lastid"] = $lastid;
        while ($data = $req->fetch(PDO::FETCH_ASSOC))
        {
            date_en_fr($date_fr, $data"date"]);
            $d"result"] .= '<p><strong>'.NomTchatUser($data"idUser2"], $dbh).'</strong> ('.$date_fr.') : '.htmlentities(utf8_decode($data"content"])).'</p>';
            $d"lastid"] = $data"id"];
        }
        $d"erreur"] = "ok";
    }
}
echo json_encode($d);
?>
<?php
  include('includes/footer.php');
?>