注意是在生命周期:mounted中:

  mounted() {
    const userAgent = window.navigator.userAgent;
    if (userAgent.indexOf("Android") > -1) {
      console.log("客户端类型:Android");
    } else if (
      userAgent.indexOf("iPhone") > -1 ||
      userAgent.indexOf("iPad") > -1 ||
      userAgent.indexOf("iPod") > -1
    ) {
      console.log("客户端类型:iOS");
    } else if (
      userAgent.indexOf("Mac OS X") > -1 ||
      userAgent.indexOf("Windows") > -1
    ) {
      console.log("客户端类型:PC");
    } else if (userAgent.indexOf("iPad") > -1) {
      console.log("客户端类型:iPad");
    } else {
      console.log("客户端类型:未知");
    }
  },