function activateMenu(element){
	showSubMenu(element);
	element.className = 'active';
}

function disactivateMenu(element){
	hideSubMenu(element);
	element.className = '';
}

function showSubMenu(element){
	var uls = element.getElementsByTagName('ul');
	for(var i=0; i< uls.length; i++){
		uls.item(i).style.visibility="visible";
	}
}
function hideSubMenu(element){
	var uls = element.getElementsByTagName('ul');
	for(var i=0; i< uls.length; i++){
		uls.item(i).style.visibility="hidden";
	}
}