var menuarray = new Array;
menuarray[0] = "subnav-research";
menuarray[1] = "subnav-people";
menuarray[2] = "subnav-emissions";
menuarray[3] = "subnav-aerosol";
menuarray[4] = "subnav-stoves";
menuarray[5] = "subnav-profbond";
menuarray[6] = "subnav-press";

function menudisplay(ref) {
	hza = document.getElementById(menuarray[ref]);
	state = hza.style.display;
	
	if (state=='block') {
		hza.style.display = 'none';
	}
	else  {
		hza.style.display = 'block';
	}
}