【函数封装】javascript判断移动端操作系统为android 或 ios 或 iphoneX

function isPhone(){
        var u = navigator.userAgent, app = navigator.appVersion;
        var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1; //g
        var isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端
        var isIphoneX = /iphone/gi.test(navigator.userAgent) && (screen.height == 812 && screen.width == 375);
        if (isAndroid) {
            return 1;//安卓操作系统
        }else if (isIOS && !isIphoneX) {
            return 2;//ios操作系统
        }else if(isIOS && isIphoneX){
            return 3; //iphoneX机型
        }
    }