function showHide(id1, id2) {
	document.getElementById(id1).style.display = 'none';
	document.getElementById(id2).style.display = 'block';
}

function navTo(curnr, nr) {
	var f = document.forms['quiz'];
	var a = f.answer;
	if (nr < 0) return;
	var c = a[0].checked || a[1].checked || a[2].checked || a[3].checked;
	if ((nr > curnr) && (!c)) return;
	f.navto.value = nr;
	f.submit();
}

function navUpdate() {
	document.getElementById('next').className = 'active';
}