function showHideStaff (){
	var d = document.getElementById ('dept')
	var s = document.getElementById ('staff')
	if (d.selectedIndex == d.options.length - 1 ) { // last one
		s.style.visibility = 'visible' ; 
	}else{
		s.style.visibility = 'hidden' ; 
		s.options[0].selected = true ;
	}
}