function subnav_ein(id)
{
	subnav = document.getElementById("subnav" + id);
	subnav.style.display = "block";
}

function subnav_aus(id)
{
	subnav = document.getElementById("subnav" + id);
	subnav.style.display = "none";
}

function subnav_alle_aus()
{
	elements = document.getElementById("nav_main").getElementsByTagName("div");
	for (i = 0; i < elements.length; i++)
		if (elements[i].className == "nav_sub") elements[i].style.display = "none";
}