var timeout     = 300;
                        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;

                        function init()
                          {}