function select_minmax(changed, min_id, max_id)
{
	min = document.getElementById(min_id);
	max = document.getElementById(max_id);
	
	if (changed == min && min.selectedIndex > max.selectedIndex) { max.selectedIndex = min.selectedIndex; }
	else if (changed == max && max.selectedIndex < min.selectedIndex) { min.selectedIndex = max.selectedIndex; }
}