代码如下，摘自：IM QQ

const os = function () {
  const ua = navigator.userAgent,
      isWindowsPhone = /(?:Windows Phone)/.test(ua),
      isSymbian = /(?:SymbianOS)/.test(ua) || isWindowsPhone,
      isAndroid = /(?:Android)/.test(ua),
      isFireFox = /(?:Firefox)/.test(ua),
      isTablet = /(?:iPad|PlayBook)/.test(ua) || (isAndroid && !/(?:Mobile)/.test(ua)) || (isFireFox && /(?:Tablet)/.test(ua)),
      isPhone = /(?:iPhone)/.test(ua) && !isTablet,
      isPc = !isPhone && !isAndroid && !isSymbian;
  return {
    isPc: isPc
  };

}();

if (!os.isPc) {
  window.location.href = '前往的移动端URL';
}