// 判断是否为IE浏览器
function isIE () {
  const bw = window.navigator.userAgent
  // ie版本 10 及以下
  const compare = (s) => bw.indexOf(s) >= 0
  // ie 11
  const ie11 = (() => 'ActiveXObject' in window)()
  return compare('MSIE') || ie11
}
isChrome() {
    const e = navigator.userAgent.toLowerCase(),
        t = /chrome/;
    return t.test(e) ? !0 : !1
}
isEdge() {
    const e = navigator.userAgent.toLowerCase(),
        t = /edge/;
    return t.test(e) ? !0 : !1
}
// IE 11 以下
isOldIE() {
    const e = navigator.userAgent.toLowerCase();
    return /msie/.test(e)
}
getBrowserVer() {
    const e = navigator.userAgent.toLowerCase();
    return (e.match(/.+(?:rv|it|ra|ie)[\/: ]([\d.]+)/) || [])[1]
}