JavaScript：用户代理检测：通过浏览器识别平台、操作系统等（Windows, Mac, iOS，iPad等）

 客户端检测经常用的方法：能力检测、怪癖检测和用户代理检测。

 能力检测：在写代码前先检测浏览器的能力。

怪癖检测：实际上是浏览器现存的bug。

用户代理检测：通过检测用户代理字符串来识别浏览器。

一般优先考虑使用 能力检测，怪癖检测是第二种选择，用户代理检测是最后一种方案。

var client = function () {
    // 引擎
    var engine = {
        ie: 0,
        gecko: 0,
        webkit: 0,
        khtml: 0,
        opera: 0,
        version: null // 版本号
    };
    // 浏览器
    var brower = {
        ie: 0,
        firefox: 0,
        safari: 0,
        konq: 0,
        opera: 0,
        chrome: 0,
        version: null // 版本号
    };

    // 平台、设备、操作系统
    var system = {
        win: false,
        mac: false,
        xll: false,// Unix

        // 移动设备
        iphone: false,
        ipod: false,
        ipad: false,
        ios: false,
        android: false,
        nokiaN: false,// 诺基亚N系列手机
        winMobile: false,

        // 游戏系统
        wii: false,// 任天堂
        ps: false
    };

    // 检测引擎和浏览器
    var ua = navigator.userAgent;
    if (window.opera) {
        engine.version = brower.version = window.opera.version();
        engine.opera = brower.opera = parseFloat(engine.version);
    } else if (/AppleWebKit\/(\S+)/.test(ua)) {
        engine.version = RegExp["$1"];
        engine.webkit = parseFloat(engine.version);

        // chrome or safari
        if (/Chrome\/(\S+)/.test(ua)) {

            if (/Edg\/(\S+)/ig.test(ua)) {
                engine.version = brower.version = RegExp["$1"];
                engine.ie = brower.ie = parseFloat(engine.version);
            } else {
                brower.version = RegExp["$1"];
                brower.chrome = parseFloat(brower.version);
            }
        } else if (/Version\/(\S+)/.test(ua)) {
            brower.version = RegExp["$1"];
            brower.safari = parseFloat(brower.version);
        } else {
            // 近似确定版本号
            var safariVersion = 1;
            if (engine.webkit < 100) {
                safariVersion = 1;
            } else if (engine.webkit < 312) {
                safariVersion = 1.2;
            } else if (engine.webkit < 412) {
                safariVersion = 1.3;
            } else {
                safariVersion = 3;
            }
            brower.safari = brower.version = safariVersion;
        }
    } else if (/KHTML\/(\S+)/.test(ua) || /Konqueror\/([^;]+)/.test(ua)) {
        engine.version = brower.version = RegExp["$1"];
        engine.khtml = brower.konq = parseFloat(brower.version);

    } else if (/rv:([^\)]+)\) Gecko\/\d{8}/.test(ua)) {
        engine.version = RegExp["$1"];
        engine.gecko = parseFloat(engine.version);

        // 确定是否是Firefox
        if (/FireFox\/(\S+)/.test(ua)) {
            brower.version = RegExp["$1"];
            brower.firefox = parseFloat(brower.version);
        }

    } else if (/MSIE ([^;]+)/.test(ua)) {
        // 不适用IE11和Edge
        engine.version = brower.version = RegExp["$1"];
        engine.ie = brower.ie = parseFloat(engine.version);
    } else if (/rv:([^\)]+)\)/.test(ua)) {
        // 判断IE11
        engine.version = brower.version = RegExp["$1"];
        engine.ie = brower.ie = parseFloat(engine.version);
    }

   
    //  检测浏览器
    brower.ie = engine.ie;
    brower.opera = engine.opera;

    // 检测平台
    var p = navigator.platform;
    system.win = p.indexOf("Win") == 0;
    system.mac = p.indexOf("Mac") == 0;
    system.xll = (p.indexOf("Linux") == 0) || (p == "Xll");

    // 检测windows操作系统
    if (system.win) {
        if (/Win(?:dows )?([^do]{2})\s?(\d+\.\d+)?/.test(ua)) {
            if (RegExp["$1"] == "NT") {
                switch (RegExp["$2"]) {
                    case "5.0":
                        system.win = "2000";
                        break;
                    case "5.1":
                        system.win = "XP";
                        break;
                    case "6.0":
                        system.win = "Vista";
                        break;
                    case "6.1":
                        system.win = "7";
                        break;
                    default:
                        system.win = "NT";
                        break;

                }
            } else if (RegExp["$1"] == "9x") {
                system.win = "ME";
            } else {
                system.win = RegExp["$1"]
            }
        }
    }

    // 移动设备
    system.iphone = ua.indexOf("iPhone") > -1;
    system.ipod = ua.indexOf("iPod") > -1;
    system.ipad = ua.indexOf("iPad") > -1;
    system.nokiaN = ua.indexOf("NokiaN") > -1;

    // windows phone
    if (system.win == "CE") {
        system.winMobile = system.win;
    } else if (system.win == "Ph") {
        if (/Windows Phone OS (\d+.\d+)/.test(us)) {
            system.win = "Phone";
            system.winMobile = parseFloat(RegExp["$1"])
        }
    }

    // 检测IOS版本
    if (system.mac && ua.indexOf("Mobile") > -1) {
        if (/CPU (?:iPhone )?OS (\d+_\d+)/.test(ua)) {
            system.ios = parseFloat(RegExp.$1.replace("_", "."));

        } else {
            system.ios = 2;
        }
    }

    // 检测Android版本
    if (/Android (\d+\.\d+)/.test(ua)) {
        system.android = parseFloat(RegExp.$1);
    }

    // 游戏系统
    system.wii = ua.indexOf("Wii") > -1;
    system.ps = /playstation/i.test(ua);

    return {
        engine: engine,
        brower: brower,
        system: system
    };

}();

 

 

Windows操作系统下部分浏览器测试结果：