function setMenuRub(nom){
	document.getElementById(nom).getElementsByTagName('a')[0].style.backgroundImage = 'url("./img/'+nom+'_roll.png")';
	document.getElementById(nom).getElementsByTagName('a')[0].href='#';
}

function preloadMenuRollImages(){
	if (document.images)
	{
	  pic_menu_qui= new Image(1,1); 
	  pic_menu_qui.src="./img/menu_qui_roll.png";
	  
	  pic_menu_que= new Image(1,1); 
	  pic_menu_que.src="./img/menu_que_roll.png";
	  
	  pic_menu_achat= new Image(1,1); 
	  pic_menu_achat.src="./img/menu_achat_roll.png";
	  
	  pic_menu_vente= new Image(1,1); 
	  pic_menu_vente.src="./img/menu_vente_roll.png";
	  
	  pic_menu_contact= new Image(1,1); 
	  pic_menu_contact.src="./img/menu_contact_roll.png";
	}
}

preloadMenuRollImages();