我根据Hermann Ingjaldsson的回答写了一个版本检测器，但是更健壮，它返回一个包含名称/版本数据的对象。它涵盖了主要的浏览器，但我不介意过多的移动浏览器和小浏览器:

function getBrowserData(nav) {
    var data = {};

    var ua = data.uaString = nav.userAgent;
    var browserMatch = ua.match(/(opera|chrome|safari|firefox|msie|trident(?=\/))\/?\s*([\d\.]+)/i) || [];
    if (browserMatch[1]) { browserMatch[1] = browserMatch[1].toLowerCase(); }
    var operaMatch = browserMatch[1] === 'chrome';
    if (operaMatch) { operaMatch = ua.match(/\bOPR\/([\d\.]+)/); }

    if (/trident/i.test(browserMatch[1])) {
        var msieMatch = /\brv[ :]+([\d\.]+)/g.exec(ua) || [];
        data.name = 'msie';
        data.version = msieMatch[1];
    }
    else if (operaMatch) {
        data.name = 'opera';
        data.version = operaMatch[1];
    }
    else if (browserMatch[1] === 'safari') {
        var safariVersionMatch = ua.match(/version\/([\d\.]+)/i);
        data.name = 'safari';
        data.version = safariVersionMatch[1];
    }
    else {
        data.name = browserMatch[1];
        data.version = browserMatch[2];
    }

    var versionParts = [];
    if (data.version) {
        var versionPartsMatch = data.version.match(/(\d+)/g) || [];
        for (var i=0; i < versionPartsMatch.length; i++) {
            versionParts.push(versionPartsMatch[i]);
        }
        if (versionParts.length > 0) { data.majorVersion = versionParts[0]; }
    }
    data.name = data.name || '(unknown browser name)';
    data.version = {
        full: data.version || '(unknown full browser version)',
        parts: versionParts,
        major: versionParts.length > 0 ? versionParts[0] : '(unknown major browser version)'
    };

    return data;
};

它可以这样使用:

var brData = getBrowserData(window.navigator || navigator);
console.log('name: ' + brData.name);
console.log('major version: ' + brData.version.major);
// etc.

在纯Javascript中，您可以在导航器上执行RegExp匹配。使用userAgent查找Firefox版本:

var uMatch = navigator.userAgent.match(/Firefox\/(.*)$/),
    ffVersion;
if (uMatch && uMatch.length > 1) {
    ffVersion = uMatch[1];
}

如果不是Firefox浏览器，ffVersion将未定义。

参见工作示例→

您可以看到浏览器显示的内容，并使用该信息记录或测试多个浏览器。

navigator.sayswho= (function(){ var ua= navigator.userAgent; var tem; var 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 'IE '+(tem[1] || ''); } if(M[1]=== 'Chrome'){ tem= ua.match(/\b(OPR|Edge)\/(\d+)/); if(tem!= null) return tem.slice(1).join(' ').replace('OPR', 'Opera'); } 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 M.join(' '); })(); console.log(navigator.sayswho); // outputs: `Chrome 62`

var ua = navigator.userAgent;

if (/Firefox\//.test(ua))
   var Firefox = /Firefox\/([0-9\.A-z]+)/.exec(ua)[1];

为此，您需要检查navigator的值。appVersion或navigator.userAgent 尝试使用:

console.log(navigator.appVersion)

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"}