(function() {
  var user_language = navigator.userLanguage || navigator.language;
  try {
    user_language = user_language.toLowerCase().slice(0, 2);
  }
  catch(err) {
  }

  var current_language;
  if (document.location.pathname.match(/\/jp-/))
    current_language = 'ja';
  else
    current_language = 'en';

  if ((current_language != user_language) && ((user_language == 'ja') || (user_language == 'en'))) {
    var new_path = document.location.pathname;
    new_path = new_path.replace(/\/\//, '/');
    if (new_path == '/') {
      new_path = '/index.html';
    }
    if (user_language == 'ja') {
      new_path = new_path.replace(/^\//, '/jp-');
    }
    else {
      new_path = new_path.replace(/^\/jp-/, '/');
    }
    var loc = document.location;
    document.location = loc.protocol + '//' + loc.host + new_path + loc.search + loc.hash;
  }
})();