var NAV=navigator; 
if ( (NAV.appName == 'Netscape') && (parseInt(NAV.appVersion) <= 4) ) { 
document.write('<LINK REL="stylesheet" HREF="js/fontns.css" TYPE="text/css">') 
} 
else { 
document.write('<LINK REL="stylesheet" HREF="js/font.css" TYPE="text/css">') 
}