js判断用户的浏览设备是移动设备还是PC

<script type="text/javascript">
    function browserRedirect() {
      var sUserAgent = navigator.userAgent.toLowerCase();
      var bIsIpad = sUserAgent.match(/ipad/i) == "ipad";
      var bIsIphoneOs = sUserAgent.match(/iphone os/i) == "iphone os";
      var bIsMidp = sUserAgent.match(/midp/i) == "midp";
      var bIsUc7 = sUserAgent.match(/rv:1.2.3.4/i) == "rv:1.2.3.4";
      var bIsUc = sUserAgent.match(/ucweb/i) == "ucweb";
      var bIsAndroid = sUserAgent.match(/android/i) == "android";
      var bIsCE = sUserAgent.match(/windows ce/i) == "windows ce";
      var bIsWM = sUserAgent.match(/windows mobile/i) == "windows mobile";
      if (bIsIpad || bIsIphoneOs || bIsMidp || bIsUc7 || bIsUc || bIsAndroid || bIsCE || bIsWM) {
        return true;
      } else {
        return false;
      }
    }

    var flag = browserRedirect();
　　if(flag){
　　　　alert("phone");
　　}else{
　　　　alert("pc");
　　}

  </script>