function GetXmlHttpObject()
{
  var objXMLHttp=null ;
  if (window.XMLHttpRequest)
  {
    objXMLHttp=new XMLHttpRequest();
   if(objXMLHttp.overrideMimeType) {objXMLHttp.overrideMimeType('text/html');}
  }
  else if (window.ActiveXObject)
  { // IE
         try {objXMLHttp = new ActiveXObject('Microsoft.XMLHTTP');}
         catch (e)
         {
            try {objXMLHttp = new ActiveXObject('Msxml2.XMLHTTP');}
            catch (e) {window.alert("Votre navigateur ne prend pas en charge l'objet XMLHTTPRequest.");}
         }
  }
return objXMLHttp;
}

function retourne(param)
{
    xmlHttp=GetXmlHttpObject();
    var url="./"+param;
    xmlHttp.onreadystatechange=function ()
    {
      if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
      {
        document.getElementById("variable").innerHTML=xmlHttp.responseText;
      }
    };
    xmlHttp.open("GET",url,true);
    xmlHttp.send(null);
}