function popup(urlpopup,width,height,scrollable) {
  var largeur=width;
  var hauteur=height;
  if(width==''){largeur=800;}
  if(height==''){hauteur=600;}
  if(scrollable==''){scrollable='no';}
  var nouvelle_fenetre=window.open(urlpopup,"_blank","toolbar=no,location=no,directories=no,menubar=no,resizable=yes,scrollbars="+scrollable+",status=no,width="+largeur+",height="+hauteur);
  if(parseInt(navigator.appVersion)>2){nouvelle_fenetre.focus();}
}