var s = 0;

function on(n)
{
	if (s == n) { return; }

	if (s)
	{
		document.getElementById('sm' + s).style.visibility = 'hidden';
	}
	document.getElementById('sm' + n).style.visibility = 'visible';
	s = n;
}

function out()
{
	if (s)
	{
		document.getElementById('sm' + s).style.visibility = 'hidden';
	}
	s = 0;
}