How can you detect the version of a browser?

Question

I\'ve been searching around for code that would let me detect if the user visiting the website has Firefox 3 or 4. All I have found is code to detect the type of browser but

Answer 1

This combines kennebec's (K) answer with Hermann Ingjaldsson's (H) answer:

• Maintains original answer's minimal code. (K)
• Works with Microsoft Edge (K)
• Extends the navigator object instead of creating a new variable/object. (K)
• Separates browser version and name into independent child objects. (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.
}