/* from http://javascript-array.com/scripts/simple_drop_down_menu/ */
			var timeout	= 500;
			var closetimer	= 0;
			var ddmenuitem	= 0;

			// open hidden layer
			function mopen(id) {	
				// cancel close timer
				mcancelclosetime();

				// close old layer
				if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
				// get new layer and show it
				ddmenuitem = document.getElementById(id);
				ddmenuitem.style.visibility = 'visible';
			}	
				
			// close showed layer
			function mclose() {
				if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
			}

			// go close timer
			function mclosetime() {
				closetimer = window.setTimeout(mclose, timeout);
			}

			// cancel close timer
			function mcancelclosetime() {
				if(closetimer) {
					window.clearTimeout(closetimer);
					closetimer = null;
				}
			}

			// close layer when click-out
			document.onclick = mclose;