Remplir automatiquement champs grace à liste

<script language="javascript" type="text/javascript" >
<!--
function rempli_sousgamme(gamme){

var xhr_object = null; 
 
if(window.XMLHttpRequest) // Firefox 
	   xhr_object = new XMLHttpRequest(); 
	else if(window.ActiveXObject) // Internet Explorer 
	   xhr_object = new ActiveXObject("Microsoft.XMLHTTP"); 
	else { // XMLHttpRequest non supporte par le navigateur 
   alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest..."); 
   return; 
	}
	

var method = "POST";
var filename = "includes/retour_java_sousliste_gamme.php";
var data = null;
var gamme_choisie = gamme;

xhr_object.open(method, filename, true);


xhr_object.onreadystatechange = function() { 
	   if(xhr_object.readyState == 4) { 
				eval(xhr_object.responseText);
				//document.getElementById('select_rub2').innerHTML = xhr_object.responseText;
			}
			}
				
xhr_object.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
data = "gamme="+gamme_choisie;
xhr_object.send(data); 		 

}

-->
</script>

<? 
header('Content-type: text/html; charset=iso-8859-1');

	include('Fichier qui contient les mots de passe');
												
	mysql_connect($db_serveur, $db_user, $db_pass);		
	mysql_select_db( $db_name);												

$SQL_liste_gamme = 'SELECT *  FROM `gamme2` WHERE type = "'.$_POST['gamme'].'"';
	
	$recup_liste_gamme = mysql_query($SQL_liste_gamme);
	
echo 'var s = document.forms["ajout"].elements["rubrique2"];'; 
	echo 's.options.length = 0;'; 
	while($r = mysql_fetch_array($recup_liste_gamme)) 
	    echo 's.options[s.options.length] = new Option("'.addslashes($r["libelle_fr"]).'", '.$r["id_gamme"].');'; 

?>