function showHide(id1, id2, i) {
	obj1 = document.getElementById(id1);
	obj2 = document.getElementById(id2);
	menuli = document.getElementById('menu').getElementsByTagName('li');

	obj1.style.display = "block";
	obj2.style.display = "none";
	menuli[i].className = "s";
	menuli[(i-1)*(-1)].className = "ns";

}