function montre(id) {
  cache_tout();
  if (document.getElementById) {
    document.getElementById(id).style.display="block";
  } else if (document.all) {
    document.all[id].style.display="block";
  } else if (document.layers) {
    document.layers[id].display="block";
  }
} 

function cache(id) {
  if (document.getElementById) {
    document.getElementById(id).style.display="none";
  } else if (document.all) {
    document.all[id].style.display="none";
  } else if (document.layers) {
    document.layers[id].display="none";
  }
}

function cache_tout() {
   cache('portage');
   cache('outils');
   cache('formation');
   cache('competence');
   cache('remuneration');
   cache('service');
   cache('contacthome');
}