导出全局变量usign CDN

如何解决导出全局变量usign CDN

我正在开发一个使用pug在服务器端呈现的网站，但是当我尝试通过cdn导入全局变量时，我总是遇到相同的错误：ReferenceError：未定义变量。

base.pug

html
  head
    block head
      Meta(name='viewport' content='width=device-width,initial-scale=1.0')
      Meta(charset='UTF-8')
      link(rel="stylesheet",href="/css/style.css")
      link(rel='shortcut icon' type='image/png' href='/img/favicon.png')
      link(rel='stylesheet' href='https://fonts.googleapis.com/css?family=Lato:300,300i,700')
      title Natours | #{title}

  body
    // HEADER
    include _header

    // CONTENT
    block content
      h1 This is a placeholder heading

    // FOOTER
    include _footer

    script(scr='https://unpkg.com/axios/dist/axios.min.js') 
    script(src='/js/mapBox.js')
    script(src='/js/login.js')

login.js：

const login = async (email,password) => {
  console.log(email,password);
  try {
    const res = await axios({
      method: 'POST',url: 'http://127.0.0.1:3000/api/v1/users/login',data: {
        email,password
      }
    });
    console.log(res);
  } catch (err) {
    console.log(err);
  }
};

const form = document
  .querySelector('.form')
  .addEventListener('submit',event => {
    event.preventDefault();
    const email = document.getElementById('email').value;
    const password = document.getElementById('password').value;
    login(email,password);
  });