旁路病毒扫描谷歌驱动器链接,并得到确认ID

function fixGoogleDriveURL(url) {
  if (url.indexOf('drive.google.com') !== -1) {
    var DocIDfull = url;
    var DocIDstart = DocIDfull.indexOf('open?id=');
    if (DocIDstart == -1) {
      // invalid
      return url;
    }
    var DocID = DocIDfull.slice(DocIDstart+8);
    url = 'https://drive.google.com/uc?export=download&id=' + DocID;
    var xhr = new XMLHttpRequest();
    xhr.onload = function () {
      if (xhr.readyState === xhr.DONE) {
        if (xhr.status === 200) {
          var token = xhr.responseText.match("/confirm=([0-9A-Za-z]+)&/");
          window.location.replace(url + '&confirm=' + token[1]);
          // should I add url += '&confirm=' + token[1] here instead of window.location?
        }
      }
    };
    xhr.open("GET", url);
    xhr.send();
  }
  return url;
}
console.log(fixGoogleDriveURL('https://drive.google.com/open?id=1C25uoL6nIqqNhex3wm8VwODsO2q2pXBt') + "\n<-- should output:\nhttps://drive.google.com/uc?export=download&id=1C25uoL6nIqqNhex3wm8VwODsO2q2pXBt&confirm=XXXXX");