LDRの未読数を表示するブックマークレット

javascript:(function () {
  const USER_NAME = 'javascripter_';
  var id = Date.now(), fid = '_' + id;
  window[fid] = function (n) {
    alert(n);
    delete window[fid];
    document.body.removeChild(script);
  };
  var script = document.createElement('script');
  script.type = 'text/javascript';
  script.src = 'http://rpc.reader.livedoor.com/notify?livedoor_id=' + USER_NAME + '&format=json&callback=' + fid + '&nocache=' + id;
  document.body.appendChild(script);
})();