var current_sub;
var now_showing;

function activatesub_only(str)
{
	var elt = document.getElementById(str);
	if (elt != null)
		elt.style.display="block";

}

function deactivatesub_only(str)
{
	var elt = document.getElementById(str);
	if (elt != null)
		elt.style.display="none";
}

function activatesub(str)
{
	deactivatesub_only(now_showing);
	activatesub_only(str);
	now_showing = str;
}

//function deactivatesub(str)
//{
//	deactivatesub_only(str);
//	activatesub_only(current_sub);
//}

function revertsub()
{
	deactivatesub_only(now_showing);
	activatesub_only(current_sub);
	now_showing = current_sub;
}