var Browser = "unbekannt";

if (navigator.appName == "Netscape")
  Browser = "NN" + navigator.appVersion.charAt(0);
else if (navigator.appName == "Microsoft Internet Explorer")
  	Browser = "MSIE" + navigator.appVersion.charAt(0);
  	
if (Browser == "NN4")
  document.writeln('<link rel=stylesheet href="nn.css" type ="text/css">');
          else if (Browser == "MSIE4")
                 document.writeln('<link rel=stylesheet href="forum.css" type ="text/css">');
               else 
                 document.writeln('<link rel=stylesheet href="forum.css" type ="text/css">');