function isWin() { return (navigator.appVersion.indexOf("Win") != -1); }
function isMac() { return (navigator.appVersion.indexOf("Mac") != -1); }
function isIE() { return (navigator.appName.indexOf("Explorer") != -1); }
function isNS() { return (navigator.appName.indexOf("Netscape") != -1); }
function isNS6() { return (navigator.userAgent.indexOf("Netscape6") != -1); }
function isSafari() { return (navigator.userAgent.indexOf("Safari") != -1); }
function isWinIE() { return isWin() && isIE(); }
function isWinNS() { return isWin() && isNS(); }
function isMacIE() { return isMac() && isIE(); }
function isMacNS() { return isMac() && isNS(); }
function isW3CDOM() { return (document.getElementById ? true : false); }
function isMSDOM() { return (document.all ? true : false); }
function isNCDOM() { return (document.layers ? true : false); }
function isDOM() { return isW3CDOM() || isMSDOM() || isNCDOM(); }

if (isWin()) {
  if (isIE()) {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/wid.css">');
  } else if (isNS6()) {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/wn6.css">');
  } else if (isNS()) {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/wnd.css">');
  } else {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/etc.css">');
  }
} else if (isMac()) {
  if (isIE()) {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/mid.css">');
  } else if (isSafari()) {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/msa.css">');
  } else if (isNS()) {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/mnd.css">');
  } else {
    document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/etc.css">');
  }
} else {
  document.writeln('<link rel="stylesheet" type="text/css" href="http://www.rcast.u-tokyo.ac.jp/ja/include/css/etc.css">');
}