浏览器简易嗅探器

document.write(navigator.userAgent);
document.write(‘<br/>‘);
document.write(navigator.platform);

var client = function(){
//引擎
    var engine = {
        ie:false,
        gecko:false,
        khtml:false,
        opera:false,
        webkit:false,
        ver:0
    };
//浏览器
    var browser = {
        ie:false,
        firefox:false,
        chrome:false,
        safari:false,
        opera:false,
        ver:0,
        name:‘‘
    };
//系统
    var system = {
        win:false,
        mac:false,
        x11:false,

        sysname:‘‘
    }


//核心监测程序
    var ua = navigator.userAgent;
    var p = navigator.platform;

    if(p.indexOf(‘Win‘) == 0){
        system.win = true;
        system.sysname = ‘Window‘;
    }else if(p.indexOf(‘Mac‘) == 0){
        system.mac = true;
        system.sysname = ‘Macintosh‘;
    }else if(p == ‘X11‘ || p.indexOf(‘Linux‘) == 0){
        system.x11 = true;
        system.sysname = ‘Linux‘;
    }

    if(window.opera){
        engine.opera = true;
        engine.ver= browser.ver = window.opera.version();
        engine.name= ‘Opera‘;
    }else if(/AppleWebKit\/(\S+)/.test(ua)){
        engine.webkit = true;
        engine.ver = RegExp[‘$1‘];
        if(/Chrome\/(\S+)/.test(ua)){
            browser.chrome = true;
            browser.ver = RegExp[‘$1‘];
            browser.name = ‘Chrome‘;
        }else{
            borwser.safari = true;
            if(/Version\/(\S+)/.test(ua)){
                browser.ver = RegExp[‘$1‘];
                browser.name = ‘safari‘;
            }
        }
    }else if(/rv:([^\)]+)\) Gecko\/\d{8}/.test(ua)){
        engine.gecko = true;
        engine.ver = RegExp[‘$1‘];
        if(/Firefox\/(\S+)/.test(ua)){
            browser.firefox = true;
            browser.ver = RegExp[‘$1‘];
            browser.name = ‘Firefox‘;
        }
    }else if(/MSIE ([^;]+)/.test(ua)){
        engine.ie = browser.ie = true;
        engine.ver = browser.ver = RegExp[‘$1‘];
        browser.name = ‘Internet Explorer‘;
    }

    return {
        engine:engine,
        browser:browser,
        system:system
    }

}();



alert(client.system.sysname + "目前使用的是" + client.browser.name + "浏览器，版本为" + client.browser.ver);