// on se crée l'objet http_request qui permettra d'appeler copix
var http_request = false;

function makeRequest(url, zone) {
      http_request = false;
      if (window.XMLHttpRequest) { // Mozilla, Safari,...
         http_request = new XMLHttpRequest();
         if (http_request.overrideMimeType) {
            http_request.overrideMimeType('text/xml');
         }
      } else if (window.ActiveXObject) { // IE
         try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
         } catch (e) {
            try {
               http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
         }
      }
      if (!http_request) {
         alert('Cannot create XMLHTTP instance');
         return false;
      }
      http_request.zoneToChange = zone; //je retiens la zone à changer

      http_request.onreadystatechange = changezone;
      http_request.open('GET', url , true);
      http_request.send(null);
   }

   function changezone(){
        if (http_request.readyState == 4) {
         if (http_request.status == 200) {
            var contenu = http_request.responseText;
            document.getElementById(http_request.zoneToChange).innerHTML=contenu;
         }
        }
   }