if (document.layers) {var NS4 = true;}
else if (document.all) {var IE4 = true;}
else if (document.getElementById) {var NS6 = true;}
isMac = (navigator.platform.indexOf("Mac") != -1)?1:0;
isLinux = (navigator.platform.indexOf("Linux") != -1)?1:0;
isWin = (navigator.platform.indexOf("Win32") != -1)?1:0;
isSun = (navigator.platform.indexOf("Sun") != -1)?1:0;