var timeout	= 500;
        var closetimer	= 0;
        var ddmenuitem	= 0;

        function menuopen(id)
        {	
	        // cancel close timer
	        menucancelclosetime();

	        // close old layer
	        if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';

	        // get new layer and show it
	        ddmenuitem = document.getElementById(id);
	        ddmenuitem.style.visibility = 'visible';

        }
        function menuclose()
        {
	        if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
        }

        function menuclosetime()
        {
	        closetimer = window.setTimeout(menuclose, timeout);
        }

        function menucancelclosetime()
        {
	        if(closetimer)
	        {
		        window.clearTimeout(closetimer);
		        closetimer = null;
	        }
        }

        document.onclick = menuclose;