方法1：

function IsPC() {
        var userAgentInfo = navigator.userAgent;
        var Agents = ["Android", "iPhone",
                    "SymbianOS", "Windows Phone",
                    "iPad", "iPod"];
        var flag = true;
        for (var v = 0; v < Agents.length; v++) {
            if (userAgentInfo.indexOf(Agents[v]) > 0) {
                flag 
 
= false;
                break;
            }
        }
        return flag;
    }

方法2：

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) ){
　　　　alert(‘PC‘);
　　}
}
browserRedirect();

方法3：

if(navigator.userAgent.match(/(iPhone|iPod|Android|ios)/i)){
    alert('移動端')
}else {
　　alert('PC端')
}

原文：https://www.cnblogs.com/bruce-gou/p/5235902.html