下载html文件展示

/**
   * 下载osshtml文件展示
   */
  downloadHtml = (url) => {
    const xhr = new XMLHttpRequest()
    xhr.open('GET', url, true)
    xhr.responseType = 'DOMString'
    xhr.onload = () => {
      document.getElementById('centerBox').innerHTML = xhr.response
    }
    xhr.send()
  }