var popup;
var IE = (navigator.appName == "Microsoft Internet Explorer") ? 1 : 0;
function fenetre(url) {
var xy="";
if (popup && !popup.closed) {
   if (IE == 1) {
      popup.location=url;
      popup.focus();
   } else {
      if (popup.screenX) {
         var x=popup.screenX;
         xy=",screenX="+x;
      }
      if (popup.screenY) {
         var y=popup.screenY;
         xy=xy+",screenY="+y;
      }
      popup.close();
      popup=window.open(url,"dessin","width=650,height=650,resizable=1,menubars=0,scrollbars=0,location=0,directories=0,status=0,toolbar=0"+xy);
   }
} else {
   popup=window.open(url,"dessin","width=650,height=650,resizable=1,menubars=0,scrollbars=0,location=0,directories=0,status=0,toolbar=0");
}
}

function retour() {
history.back();
}