NS4 = (document.layers);
 IE4 = (document.all);
 ver4 = (NS4 || IE4);   
 isMac = (navigator.appVersion.indexOf("Mac") != -1);
 isMenu = (NS4 || (IE4 && !isMac));

 function popUp(){return};
 function popDown(){return};

 if (!ver4) event = null;