var vitesse      = 80;
var top_menu     = 95;
var top_menu_max = 108;

function menu_defilant(obj) {
	element = document.getElementById(obj)
	element.style.top = top_menu + 'px';
	
	top_menu++;
	if(top_menu < top_menu_max){ 
      window.setTimeout("menu_defilant('"+obj+"')",vitesse); // Re-lance la fonction 
  }
}