获取cookie

function getCookie(cookie_name: string) {
  const allcookies = document.cookie
  let value = ''
  let cookie_pos = allcookies.indexOf(cookie_name)
  if (cookie_pos !== -1) {
      cookie_pos = cookie_pos + cookie_name.length + 1
      let cookie_end = allcookies.indexOf(';', cookie_pos)
      if (cookie_end === -1) {
        cookie_end = allcookies.length
      }
      value = unescape(allcookies.substring(cookie_pos, cookie_end))
  }
  return value
}