ua=navigator.userAgent;
l='<LINK rel="stylesheet" type="text/css" href="';
c='.css">';
if (ua.indexOf('IE 4')!=-1)document.write(l+'ie4'+c);
if (ua.indexOf('IE 5')!=-1)document.write(l+'ie5'+c);
if (ua.indexOf('IE 6')!=-1)document.write(l+'ie6'+c);
if (ua.indexOf("Opera 3")!=-1)document.write(l+'op3'+c);
else if (ua.indexOf("compatible")==-1) {
  if (ua.indexOf("/4")!=-1)document.write(l+'nn4'+c);
  if (ua.indexOf("/5")!=-1)document.write(l+'nn6'+c);
}