function nav_active(nav_id)
{
	document.getElementById("nav_" + nav_id).className = "nav_active";
}

function nav_inactive(nav_id)
{
	document.getElementById("nav_" + nav_id).className = "";
}

function map_active(nav_id)
{
	document.getElementById(nav_id).className = "map_active";
}

function map_inactive(nav_id)
{
	document.getElementById(nav_id).className = "";
}