if (parseInt(navigator.appVersion) >= 4) {
  var IE4 = (navigator.appVersion.indexOf("MSIE") > 0);
  var NN4 = (navigator.appName == "Netscape");
  var OS;
  if (navigator.appVersion.indexOf("Win") > 0) {OS = "Windows"};
  if (navigator.appVersion.indexOf("Mac") > 0) {OS = "MacOS";}
  switch (OS) {
    case "Windows":
      if (IE4 > 0) document.write ("<LINK href='/common/new_win_ie.css' rel='stylesheet' type='text/css'>");
      if (NN4 > 0) document.write ("<LINK href='/common/new_win_nn.css' rel='stylesheet' type='text/css'>");
      break;
    case "MacOS":
      if (IE4 > 0) document.write ("<LINK href='/common/mac_ie.css' rel='stylesheet' type='text/css'>");
      if (NN4 > 0) document.write ("<LINK href='/common/mac_nn.css' rel='stylesheet' type='text/css'>");
      break;
    }
}