lastElement = 's';
		
		// show a hidden element
		function display(panelName) {
			// first hide the last displayed element
			hide(lastElement);

			// show the new element
			document.getElementById(panelName).style.visibility = 'visible';
			document.getElementById(panelName).style.display = 'block';
			
			// remember this element
			lastElement = panelName;
			return false;
		}// end function display(panelName)

		// hide a visible element
		function hide(panelName) {
			document.getElementById(panelName).style.visibility = 'hidden';
			document.getElementById(panelName).style.display = 'none';
		}// end function hide(panelName)