SOURCE

function myAsyncFun (url) {
  return new Promise ( (resolve, reject) => {
    const xhr = new XMLHttpRequest()
    xhr.open('GET', url)
    xhr.onload = () => {resolve(xhr.responseText)}
    xhr.onerror = () => {reject(xhr.statusText)}
    xhr.send()
  })
}

const url = 'http://bj-m-213985a:8099/public/live/play?appname=newsapp&appver=620&applt=ios&tags=newsapp&program_token=20001043'

myAsyncFun(url).then( (response) => {
  console.log('加载成功', response)
  throw new Error()
}, () => {
  console.log('加载失败')
}).catch( () => {
  console.log('捉到catch')
})