$('#contenu').bind('onAjaxNavReq',function () {
 $('#contenu').animate(
  {opacity: 0},
  {
   duration: 'fast',
   complete: afficherSablier
 });
});
$('#contenu').bind('onAjaxNavLoad',function (){
 retirerSablier();
 $('#contenu').animate({opacity: 1}, 'fast');
});