function switch_nav_on(nav_id) {		
		this_nav = document.getElementById(nav_id);
		this_nav.src = "/images/"+nav_id+"_over.gif";
		
		this_nav_link = document.getElementById(nav_id+"_link");
		this_nav_link.className = "navitemover";
}

function switch_nav_off(nav_id) {
		this_nav = document.getElementById(nav_id);
		this_nav.src = "/images/"+nav_id+".gif";

		this_nav_link = document.getElementById(nav_id+"_link");
		this_nav_link.className = "navitem";
}