function mainMenu(){
$(" #aiNavigation ul ").css({display: "none"});
$(" #aiNavigation li").hover(function(){
		$(this).find('ul:first').css({visibility: "visible",display: "none"}).slideDown(400);
		},function(){
		$(this).find('ul:first').css({visibility: "hidden"});
		});
}

function initNavigation(){
	$(document).ready(function(){
		mainMenu();
	});
}