function navigation(){
	
	//collapse/expand menus
	var sections = new Array("home","portfolio","about");
	
	
	//highlight relevant links
	if(window.main_nav && document.getElementById("main-nav-" + main_nav)){
	document.getElementById("main-nav-" + main_nav).className = "on";
	}
}

function secondarynavigation(){

	//collapse/expand menus
	var sections = new Array("All","Landscapes","Panoramas","Infrareds","Architecture");

	//highlight relevant links
	
	if(window.secondary_nav && document.getElementById("secondary-nav-" + secondary_nav)){
	document.getElementById("secondary-nav-" + secondary_nav).className = "onsecondary";

	}
}