var nIdPrev = "1";
var nSubIdPrev = "1";

function show_nav(nId)
{
	hide_nav();
	document.getElementById('nav_' + nId).style.visibility = "visible";
	document.getElementById('head_' + nId).className = "button active";
	nIdPrev = nId;
}

function hide_nav()
{
	document.getElementById('nav_' + nIdPrev).style.visibility = "hidden";
	if(document.getElementById('menu_' + nIdPrev).className != "nav active")
	{
		document.getElementById('head_' + nIdPrev).className = "button";
	}
}

function show_subnav(nId)
{
	hide_subnav();
	document.getElementById('sub_' + nId).style.visibility = "visible";
	var vParent = document.getElementById('sub_' + nId).parentNode;
	vParent.style.backgroundColor = "#004f9e";
	nSubIdPrev = nId;
}

function hide_subnav()
{
	document.getElementById('sub_' + nSubIdPrev).style.visibility = "hidden";
	var vParent = document.getElementById('sub_' + nSubIdPrev).parentNode;
	vParent.style.backgroundColor = "";
}