检测用户使用的的设备信息

以下是完整的用户代理字符串检测脚本，包括检测呈现引擎、平台、Windows 操作系统、移动设备
和游戏系统。

var client = function(){
    //呈现引擎
    var engine = {
            ie: 0,
            gecko: 0,
            webkit: 0,
            khtml: 0,
            opera: 0,

        //完整的版本号
        ver: null 
    };

    //浏览器
    var browser = {
        //主要浏览器 
        ie: 0, 
        firefox: 0, 
        safari: 0,   
        konq: 0,  
        opera: 0,
        chrome: 0,

        //具体的版本号
        ver: null 
    };

    //平台、设备和操作系统 
    var system = {
        win: false,
        mac: false,
        x11: false,

        //移动设备
        iphone: false, 
        ipod: false, 
        ipad: false,
        ios: false,  
        android: false, 
        nokiaN: false, 
        winMobile: false, 

        //游戏系统  
        wii: false,  
        ps: false

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

            //确定是 Chrome 还是 Safari
            if (/Chrome\/(\S+)/.test(ua)){
                    browser.ver = RegExp["$1"];
                    browser.chrome = parseFloat(browser.ver);
            } else if (/Version\/(\S+)/.test(ua)){
                browser.ver = RegExp["$1"];
                browser.safari = parseFloat(browser.ver);
            } else {
                //近似地确定版本号
                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 = 2;
                }
                browser.safari = browser.ver = safariVersion;
            }
        } else if (/KHTML\/(\S+)/.test(ua) || /Konqueror\/([^;]+)/.test(ua)){ 
            engine.ver = browser.ver = RegExp["$1"];
            engine.khtml = browser.konq = parseFloat(engine.ver);
        } else if (/rv:([^\)]+)\) Gecko\/\d{8}/.test(ua)){
            engine.ver = RegExp["$1"];
            engine.gecko = parseFloat(engine.ver);

            //确定是不是 Firefox
            if (/Firefox\/(\S+)/.test(ua)){
                browser.ver = RegExp["$1"];
                browser.firefox = parseFloat(browser.ver);
            }
            } else if (/MSIE ([^;]+)/.test(ua)){
                engine.ver = browser.ver = RegExp["$1"];
                engine.ie = browser.ie = parseFloat(engine.ver);
            }

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

            //检测平台
            var p = navigator.platform;
            system.win = p.indexOf("Win") == 0;
            system.mac = p.indexOf("Mac") == 0;
            system.x11 = (p == "X11") || (p.indexOf("Linux") == 0); 

            //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 mobile
        if (system.win == "CE"){
             system.winMobile = system.win;
        } else if (system.win == "Ph"){
             if(/Windows Phone OS (\d+.\d+)/.test(ua)){;
               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; //不能真正检测出来，所以只能猜测
            } 
        } 

        //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); 

        //返回这些对象  
        return {
           engine:     engine,
           browser:    browser,
           system:     system
        }; 
}();