我想分享我为我必须解决的问题而编写的代码。它在大多数主流浏览器中都进行了测试，对我来说，它就像一个魅力!

似乎这段代码与其他答案非常相似，但它进行了修改，以便我可以使用它而不是我最近错过的jquery浏览器对象，当然它是上述代码的组合，从我的部分我做了一些改进:

(function($, ua){

var M = ua.match(/(opera|chrome|safari|firefox|msie|trident(?=\/))\/?\s*(\d+)/i) || [],
    tem, 
    res;

if(/trident/i.test(M[1])){
    tem = /\brv[ :]+(\d+)/g.exec(ua) || [];
    res = 'IE ' + (tem[1] || '');
}
else if(M[1] === 'Chrome'){
    tem = ua.match(/\b(OPR|Edge)\/(\d+)/);
    if(tem != null) 
        res = tem.slice(1).join(' ').replace('OPR', 'Opera');
    else
        res = [M[1], M[2]];
}
else {
    M = M[2]? [M[1], M[2]] : [navigator.appName, navigator.appVersion, '-?'];
    if((tem = ua.match(/version\/(\d+)/i)) != null) M = M.splice(1, 1, tem[1]);
    res = M;
}

res = typeof res === 'string'? res.split(' ') : res;

$.browser = {
    name: res[0],
    version: res[1],
    msie: /msie|ie/i.test(res[0]),
    firefox: /firefox/i.test(res[0]),
    opera: /opera/i.test(res[0]),
    chrome: /chrome/i.test(res[0]),
    edge: /edge/i.test(res[0])
}

})(typeof jQuery != 'undefined'? jQuery : window.$, navigator.userAgent);

 console.log($.browser.name, $.browser.version, $.browser.msie); 
// if IE 11 output is: IE 11 true

这个页面似乎有一个非常漂亮的代码片段，它只使用appString和appVersion属性作为最后的手段，因为它声称它们在某些浏览器中是不可靠的。 页面上的代码如下:

var nVer = navigator.appVersion;
var nAgt = navigator.userAgent;
var browserName  = navigator.appName;
var fullVersion  = ''+parseFloat(navigator.appVersion); 
var majorVersion = parseInt(navigator.appVersion,10);
var nameOffset,verOffset,ix;

// In Opera 15+, the true version is after "OPR/" 
if ((verOffset=nAgt.indexOf("OPR/"))!=-1) {
 browserName = "Opera";
 fullVersion = nAgt.substring(verOffset+4);
}
// In older Opera, the true version is after "Opera" or after "Version"
else if ((verOffset=nAgt.indexOf("Opera"))!=-1) {
 browserName = "Opera";
 fullVersion = nAgt.substring(verOffset+6);
 if ((verOffset=nAgt.indexOf("Version"))!=-1) 
   fullVersion = nAgt.substring(verOffset+8);
}
// In MSIE, the true version is after "MSIE" in userAgent
else if ((verOffset=nAgt.indexOf("MSIE"))!=-1) {
 browserName = "Microsoft Internet Explorer";
 fullVersion = nAgt.substring(verOffset+5);
}
// In Chrome, the true version is after "Chrome" 
else if ((verOffset=nAgt.indexOf("Chrome"))!=-1) {
 browserName = "Chrome";
 fullVersion = nAgt.substring(verOffset+7);
}
// In Safari, the true version is after "Safari" or after "Version" 
else if ((verOffset=nAgt.indexOf("Safari"))!=-1) {
 browserName = "Safari";
 fullVersion = nAgt.substring(verOffset+7);
 if ((verOffset=nAgt.indexOf("Version"))!=-1) 
   fullVersion = nAgt.substring(verOffset+8);
}
// In Firefox, the true version is after "Firefox" 
else if ((verOffset=nAgt.indexOf("Firefox"))!=-1) {
 browserName = "Firefox";
 fullVersion = nAgt.substring(verOffset+8);
}
// In most other browsers, "name/version" is at the end of userAgent 
else if ( (nameOffset=nAgt.lastIndexOf(' ')+1) < 
          (verOffset=nAgt.lastIndexOf('/')) ) 
{
 browserName = nAgt.substring(nameOffset,verOffset);
 fullVersion = nAgt.substring(verOffset+1);
 if (browserName.toLowerCase()==browserName.toUpperCase()) {
  browserName = navigator.appName;
 }
}
// trim the fullVersion string at semicolon/space if present
if ((ix=fullVersion.indexOf(";"))!=-1)
   fullVersion=fullVersion.substring(0,ix);
if ((ix=fullVersion.indexOf(" "))!=-1)
   fullVersion=fullVersion.substring(0,ix);

majorVersion = parseInt(''+fullVersion,10);
if (isNaN(majorVersion)) {
 fullVersion  = ''+parseFloat(navigator.appVersion); 
 majorVersion = parseInt(navigator.appVersion,10);
}

document.write(''
 +'Browser name  = '+browserName+'<br>'
 +'Full version  = '+fullVersion+'<br>'
 +'Major version = '+majorVersion+'<br>'
 +'navigator.appName = '+navigator.appName+'<br>'
 +'navigator.userAgent = '+navigator.userAgent+'<br>'
)

为什么不另一个解决方案:

navigator.userAgent.includes("Firefox")? log("Mozilla") :log("Chrome")

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。

看看navigator。userAgent - Firefox/xxx.xxx. xxx。XXX是在结尾指定的。

这让我有了火狐的版本，

    let versionNumber = parseInt(window.navigator.userAgent.match(/Firefox\/([0- 
    9]+)\./)[1]);