使用这个:http://www.quirksmode.org/js/detect.html

alert(BrowserDetect.browser); // will say "Firefox"
alert(BrowserDetect.version); // will say "3" or "4"

加上我自己对赫尔曼答案的实现。我需要操作系统检测，所以它被添加。还包括一些ES6代码(因为我们有一个转译器)，你可能需要es5化。

detectClient() {
    let nav = navigator.appVersion,
        os = 'unknown',
        client = (() => {
            let agent = navigator.userAgent,
                engine = agent.match(/(opera|chrome|safari|firefox|msie|trident(?=\/))\/?\s*(\d+)/i) || [],
                build;

            if(/trident/i.test(engine[1])){
                build = /\brv[ :]+(\d+)/g.exec(agent) || [];
                return {browser:'IE', version:(build[1] || '')};
            }

            if(engine[1] === 'Chrome'){
                build = agent.match(/\bOPR\/(\d+)/);

                if(build !== null) {
                    return {browser: 'Opera', version: build[1]};
                }
            }

            engine = engine[2] ? [engine[1], engine[2]] : [navigator.appName, nav, '-?'];

            if((build = agent.match(/version\/(\d+)/i)) !== null) {
                engine.splice(1, 1, build[1]);
            }

            return {
              browser: engine[0],
              version: engine[1]
            };
        })();

    switch (true) {
        case nav.indexOf('Win') > -1:
            os = 'Windows';
        break;
        case nav.indexOf('Mac') > -1:
            os = 'MacOS';
        break;
        case nav.indexOf('X11') > -1:
            os = 'UNIX';
        break;
        case nav.indexOf('Linux') > -1:
            os = 'Linux';
        break;
    }        

    client.os = os;
    return client;
}

返回:对象{浏览器:"Chrome"，版本:"50"，操作系统:"UNIX"}

jQuery可以很好地处理这个问题(jQuery.browser)

var ua = $.browser;
if ( ua.mozilla && ua.version.slice(0,3) == "1.9" ) {
    alert( "Do stuff for firefox 3" );
}

编辑:正如Joshua在他的评论下面所写的，jQuery。jQuery自1.9版起不再支持browser属性(详情请参阅jQuery 1.9发布说明)。 jQuery开发团队建议使用更完整的方法，例如使用Modernizr库调整UI。

这里有更好的兼容性@kennebec snippet; 将返回浏览器名称和版本(返回72而不是72.0.3626.96)。

在Safari, Chrome, Opera, Firefox, IE, Edge, UCBrowser上测试，也在移动设备上测试。

function browser() {
    var userAgent = navigator.userAgent,
        match = userAgent.match(/(opera|chrome|crios|safari|ucbrowser|firefox|msie|trident(?=\/))\/?\s*(\d+)/i) || [],
        result = {},
        tem;

    if (/trident/i.test(match[1])) {
        tem = /\brv[ :]+(\d+)/g.exec(userAgent) || [];
        result.name = "Internet Explorer";
    } else if (match[1] === "Chrome") {
        tem = userAgent.match(/\b(OPR|Edge)\/(\d+)/);

        if (tem && tem[1]) {
            result.name = tem[0].indexOf("Edge") === 0 ? "Edge" : "Opera";
        }
    }
    if (!result.name) {
        tem = userAgent.match(/version\/(\d+)/i); // iOS support
        result.name = match[0].replace(/\/.*/, "");

        if (result.name.indexOf("MSIE") === 0) {
            result.name = "Internet Explorer";
        }
        if (userAgent.match("CriOS")) {
            result.name = "Chrome";
        }

    }
    if (tem && tem.length) {
        match[match.length - 1] = tem[tem.length - 1];
    }

    result.version = Number(match[match.length - 1]);

    return result;
}

浏览器JavaScript库提供了此功能。

if (bowser.msie && bowser.version <= 6) {
  alert('Hello China');
}

它似乎保养得很好。

这结合了kennebec的(K)答案和Hermann Ingjaldsson的(H)答案:

维护原始答案的最小代码。(K) 使用Microsoft Edge (K) 扩展导航器对象，而不是创建新的变量/对象。(K) 将浏览器版本和名称分离为独立的子对象。(H)

navigator.browserSpecs = (function(){ var ua = navigator.userAgent, tem, M = ua.match(/(opera|chrome|safari|firefox|msie|trident(?=\/))\/?\s*(\d+)/i) || []; if(/trident/i.test(M[1])){ tem = /\brv[ :]+(\d+)/g.exec(ua) || []; return {name:'IE',version:(tem[1] || '')}; } if(M[1]=== 'Chrome'){ tem = ua.match(/\b(OPR|Edge)\/(\d+)/); if(tem != null) return {name:tem[1].replace('OPR', 'Opera'),version:tem[2]}; } M = M[2]? [M[1], M[2]]: [navigator.appName, navigator.appVersion, '-?']; if((tem = ua.match(/version\/(\d+)/i))!= null) M.splice(1, 1, tem[1]); return {name:M[0], version:M[1]}; })(); console.log(navigator.browserSpecs); //Object { name: "Firefox", version: "42" } if (navigator.browserSpecs.name == 'Firefox') { // Do something for Firefox. if (navigator.browserSpecs.version > 42) { // Do something for Firefox versions greater than 42. } } else { // Do something for all other browsers. }