function switchMenu(obj) {
	var divArray = Array('sectionNAC', 'sectionOS', 'sectionHCY','sectionFE');
	var selectedEl = divArray[ obj ];
	var el = document.getElementById(selectedEl);
		
	for(i=0; i < divArray.length; i++) {

		if ( divArray[i] == selectedEl ) {
			if ( el.style.display == '' || el.style.display == 'none' ) {
				el.style.display = 'block';
			} else {
				el.style.display = 'none';
			}
		} else {
			
			var otherEl = document.getElementById( divArray[i] );
			otherEl.style.display = 'none';
		}
		
	}
	

}