-PHP- script mini chat

Bonjour,
voivi mon script de chat mais je sais pas pourquoi il affiche que le premier message posté et les autre ne les envoie pas a la base de donnees :


<?php
if (isset($_POST['user']) AND isset($_POST['message']))
{
if ($_POST['user'] != NULL AND $_POST['message'] != NULL)
{
mysql_connect("localhost", "root", "");
mysql_select_db("test");

$message = mysql_real_escape_string(htmlspecialchars($_POST['message']));
$user = mysql_real_escape_string(htmlspecialchars($_POST['user']));

mysql_query("INSERT INTO chat VALUES('', '$user', '$message')");

mysql_close();
}
}?>

<form action="test1.php" method="post">
<p>
Votre pseudo: <input type="text" name="user" />

Votre message: <input type="text" name="message" />

<input type="submit" value="Wazaaaaa" />
</p>
</form>

<?php
mysql_connect("localhost", "root", "");
mysql_select_db("test");
$reponse = mysql_query("SELECT * FROM chat ORDER BY ID")or die(mysql_error());
mysql_close();
while ($donnees = mysql_fetch_array($reponse) )
{
?>
<p><strong><?php echo $donnees['user']; ?></strong> : <?php echo $donnees['message']; ?></p>
<?php
}

?>