function ajax_test()
{
   alert("test");
   return true;
}

var xmlHttp=new Array();

modeSynchrone = false;

function getXmlHttpObject(indice)
{
	return xmlHttp[indice];
}

function ajax_init(indice)
{
   xmlHttp[indice] = null;
   
   try
   {
      // Firefox, Opera 8.0+, Safari
      xmlHttp[indice]=new XMLHttpRequest();

   }
   catch (e)
   {
      // Internet Explorer
      try
      {
         xmlHttp[indice]=new ActiveXObject("Msxml2.XMLHTTP");
      }
      catch (e)
      {
         try
         {
            xmlHttp[indice]=new ActiveXObject("Microsoft.XMLHTTP");
         }
         catch (e)
         {
            alert("Your browser does not support AJAX!");
            return false;
         }
      }
   }
   
   if (xmlHttp[indice]!=null)
   {
      return true;
   }
   else
   {
      return false;
   }
}

function ajax_global(indice, idRetour, FichierReponseEtParams)
{
	if(ajax_init(indice))
	{
		//on définit l'appel de la fonction au retour serveur
		if(!modeSynchrone)
		{
			getXmlHttpObject(indice).onreadystatechange = function() {
				state_change_global(indice, idRetour, modeSynchrone);
			}
		}
		
		//on appelle le fichier reponse
		getXmlHttpObject(indice).open("GET", FichierReponseEtParams, !modeSynchrone);
		getXmlHttpObject(indice).send(null);
		
		if(modeSynchrone)
		{
			state_change_global(indice, idRetour, modeSynchrone);
		}
	}
	else
	{
		alert("Your browser does not support XMLHTTP.");
	}
}


function state_change_global(indice, idRetour, modeSynchrone)
{
	if(modeSynchrone)
	{
		document.getElementById(idRetour).innerHTML = getXmlHttpObject(indice).responseText;
		document.getElementById(idRetour).style.display = "block";
	}
	else
	{
		if (getXmlHttpObject(indice).readyState==4)
		{
			// 4 = "loaded"
			if (getXmlHttpObject(indice).status==200)
			{
				// 200 = "OK"
				document.getElementById(idRetour).innerHTML = getXmlHttpObject(indice).responseText;
				document.getElementById(idRetour).style.display = "block";
			}
			else
			{
				alert("Problem retrieving data:" + getXmlHttpObject(indice).statusText);
			}
		}
	}
}

function efface_zone_principale()
{
   document.getElementById("zone_principale").innerHTML = "";
   document.getElementById("zone_principale").style.visibility = "hidden";
}