[白板]JSONP

function jsonp (url) {
    return new Promise((resolve, reject) => {
      var fn = function (data) => {
        if (data.code == 200) {
          resolve(data)
      } else {
          reject(data)
      }
    }
    var script = document.createElement('script');
    script.src = 'url?callback=fn';
    document.body.append(script)
  })
}