Passage de variables via formulaire

<h1>Edit my Profile</h1>

<form id="edit" method="post" action="//localhost/wordpresstest/test_to_remove.php" >
	<table>
		<tr>
			<td>
				<label for="username">Username :</label>
			</td>	
			<td>
				<input type="text" class="disabledbutton" name="username" id="username" value="<?php echo wp_get_current_user()->user_login?>" disabled="disabled" size="40" maxlength="10" /> 
				(the user name can't be changed)
			</td>	
		</tr>
		<tr>
			<td>
				<label for="firstname">First Name :</label>
			</td>	
			<td>
				<input type="text" name="firstname" id="firstname"  size="40" maxlength="30" /> 
			</td>	
		</tr>
		<tr>
			<td>
				<label for="lastname">Last Name :</label>
			</td>	
			<td>
				<input type="text" name="lastname" id="lastname"  size="40" maxlength="30" /> 

			</td>	
		</tr>
		<tr>
			<td>
				<label for="email">Email :</label>
			</td>	
			<td>
				<input type="text" name="email" id="email" value="<?php echo wp_get_current_user()->user_email?>" size="40" maxlength="40" /> 
			</td>	
		</tr>
	</table>
	<br>
	<div align="center" ><input type="submit" value="modify"/></div>
</form>

<?php
 echo test1;
  //récupération des valeurs des champs:
if (isset($_POST['username'])){
		$username     = $_POST['username'] ;
		echo BRAVO;
} else{
			echo 'pas de username';
}
  $firstname    = $_POST["firstname"] ;

  $lastname     = $_POST["lastname"] ;

  $email        = $_POST["emai"] ; 
echo $username;  
echo test2;

  //connection au serveur:
  $cnx = mysql_connect( "localhost", "root", "octis" ) ;
 
  //sélection de la base de données:
  $db = mysql_select_db( "octiswordpress" ) ;
 
  //création de la requête SQL:
  $sql = "UPDATE wp_users SET user_firstname='STEPHANE', user_lastname='$lastname', user_email='$email' WHERE user_login='$username'" ; 
   //exécution de la requête SQL:
  $requete = mysql_query($sql, $cnx) or die( mysql_error() ) ;
  //affichage des résultats, pour savoir si l'insertion a marchée:
  if($requete)
  {
    echo("La modif a été correctement effectuée") ;
  }
  else
  {
    echo("L'insertion à échouée") ;
  }
?>

<?php
   echo (!empty($_POST['firstname'])) ? $_POST['firstname'] : "Bon ba problème :)";
?>

<?php echo wp_get_current_user()->user_login; ?>

<input type="text" class="disabledbutton" name="username" id="username" value="<?php echo wp_get_current_user()->user_login?>" disabled="disabled" size="40" maxlength="10" />