function selectDptPorteur(select){
  $$(".li_contactDpt").each(function(obj){obj.style.display="none";});
  elemSelected = "li_contactDpt_"+select.options[select.selectedIndex].getAttribute("dep");
  $(elemSelected).style.display="block";
  $("div_formContact").style.display="block";
  $("inpt_dest").value = select.options[select.selectedIndex].getAttribute("mail");
}