function parseMetadata(code) {
  if(code===undefined){
      code=GM_info.scriptMetaStr
  }
  let issub = false;
  let regex = /\/\/\s*==UserScript==([\s\S]+?)\/\/\s*==\/UserScript==/m;
  let header = regex.exec(code);
  if (!header) {
    regex = /\/\/\s*==UserSubscribe==([\s\S]+?)\/\/\s*==\/UserSubscribe==/m;
    header = regex.exec(code);
    if (!header) {
      return null;
    }
    issub = true;
  }
  regex = /\/\/\s*@([\S]+)((.+?)$|$)/gm;
  const ret = {};
  let meta = regex.exec(header[1]);
  while (meta !== null) {
    const [key, val] = [meta[1].toLowerCase().trim(), meta[2].trim()];
    let values = ret[key];
    if (values == null) {
      values = [];
    }
    values.push(val);
    ret[key] = values;
    meta = regex.exec(header[1]);
  }
  if (ret.name === undefined) {
    return null;
  }
  if (Object.keys(ret).length < 3) {
    return null;
  }
  if (!ret.namespace) {
    ret.namespace = [""];
  }
  if (issub) {
    ret.usersubscribe = [];
  }
  return ret;
}