JavaScript for detecting browser language preference [duplicate]

Answer 1

If you have control of a backend and are using django, a 4 line implementation of Dan's idea is:

def get_browser_lang(request):
if request.META.has_key('HTTP_ACCEPT_LANGUAGE'):
    return JsonResponse({'response': request.META['HTTP_ACCEPT_LANGUAGE']})
else:
    return JsonResponse({'response': settings.DEFAULT_LANG})

then in urls.py:

url(r'^browserlang/$', views.get_browser_lang, name='get_browser_lang'),

and on the front end:

$.get(lg('SERVER') + 'browserlang/', function(data){
    var lang_code = data.response.split(',')[0].split(';')[0].split('-')[0];
});

(you have to set DEFAULT_LANG in settings.py of course)

Answer 2

I came across this piece of code to detect browser's language in Angular Translate module, which you can find the source here. I slightly modified the code by replacing angular.isArray with Array.isArray to make it independent of Angular library.

var getFirstBrowserLanguage = function () {
    var nav = window.navigator,
    browserLanguagePropertyKeys = ['language', 'browserLanguage', 'systemLanguage', 'userLanguage'],
    i,
    language;

    // support for HTML 5.1 "navigator.languages"
    if (Array.isArray(nav.languages)) {
      for (i = 0; i < nav.languages.length; i++) {
        language = nav.languages[i];
        if (language && language.length) {
          return language;
        }
      }
    }

    // support for other well known properties in browsers
    for (i = 0; i < browserLanguagePropertyKeys.length; i++) {
      language = nav[browserLanguagePropertyKeys[i]];
      if (language && language.length) {
        return language;
      }
    }

    return null;
  };

console.log(getFirstBrowserLanguage());

Answer 3

let lang = window.navigator.languages ? window.navigator.languages[0] : null;
    lang = lang || window.navigator.language || window.navigator.browserLanguage || window.navigator.userLanguage;

let shortLang = lang;
if (shortLang.indexOf('-') !== -1)
    shortLang = shortLang.split('-')[0];

if (shortLang.indexOf('_') !== -1)
    shortLang = shortLang.split('_')[0];

console.log(lang, shortLang);

I only needed the primary component for my needs, but you can easily just use the full string. Works with latest Chrome, Firefox, Safari and IE10+.

Answer 4

I've been using Hamid's answer for a while, but it in cases where the languages array is like ["en", "en-GB", "en-US", "fr-FR", "fr", "en-ZA"] it will return "en", when "en-GB" would be a better match.

My update (below) will return the first long format code e.g. "en-GB", otherwise it will return the first short code e.g. "en", otherwise it will return null.

function getFirstBrowserLanguage() {
        var nav = window.navigator,
            browserLanguagePropertyKeys = ['language', 'browserLanguage', 'systemLanguage', 'userLanguage'],
            i,
            language,
            len,
            shortLanguage = null;

        // support for HTML 5.1 "navigator.languages"
        if (Array.isArray(nav.languages)) {
            for (i = 0; i < nav.languages.length; i++) {
                language = nav.languages[i];
                len = language.length;
                if (!shortLanguage && len) {
                    shortLanguage = language;
                }
                if (language && len>2) {
                    return language;
                }
            }
        }

        // support for other well known properties in browsers
        for (i = 0; i < browserLanguagePropertyKeys.length; i++) {
            language = nav[browserLanguagePropertyKeys[i]];
            //skip this loop iteration if property is null/undefined.  IE11 fix.
            if (language == null) { continue; } 
            len = language.length;
            if (!shortLanguage && len) {
                shortLanguage = language;
            }
            if (language && len > 2) {
                return language;
            }
        }

        return shortLanguage;
    }

console.log(getFirstBrowserLanguage());

Update: IE11 was erroring when some properties were undefined. Added a check to skip those properties.

Answer 5

I can't find a single reference that state that it's possible without involving the serverside.

MSDN on:

• navigator.browserLanguage
• navigator.systemLanguage
• navigator.userLanguage

From browserLanguage:

In Microsoft Internet Explorer 4.0 and earlier, the browserLanguage property reflects the language of the installed browser's user interface. For example, if you install a Japanese version of Windows Internet Explorer on an English operating system, browserLanguage would be ja.

In Internet Explorer 5 and later, however, the browserLanguage property reflects the language of the operating system regardless of the installed language version of Internet Explorer. However, if Microsoft Windows 2000 MultiLanguage version is installed, the browserLanguage property indicates the language set in the operating system's current menus and dialogs, as found in the Regional Options of the Control Panel. For example, if you install a Japanese version of Internet Explorer 5 on an English (United Kingdom) operating system, browserLanguage would be en-gb. If you install Windows 2000 MultiLanguage version and set the language of the menus and dialogs to French, browserLanguage would be fr, even though you have a Japanese version of Internet Explorer.

Note This property does not indicate the language or languages set by the user in Language Preferences, located in the Internet Options dialog box.

Furthermore, it looks like browserLanguage is deprecated cause IE8 doesn't list it

Answer 6

Dan Singerman's answer has an issue that the header fetched has to be used right away, due to the asynchronous nature of jQuery's ajax. However, with his google app server, I wrote the following, such that the header is set as part of the initial set up and can be used at later time.

<html>
<head>
<script>

    var bLocale='raw'; // can be used at any other place

    function processHeaders(headers){
        bLocale=headers['Accept-Language'];
        comma=bLocale.indexOf(',');
        if(comma>0) bLocale=bLocale.substring(0, comma);
    }

</script>

<script src="jquery-1.11.0.js"></script>

<script type="application/javascript" src="http://ajaxhttpheaders.appspot.com?callback=processHeaders"></script>

</head>
<body>

<h1 id="bLocale">Should be the browser locale here</h1>

</body>

<script>

    $("#bLocale").text(bLocale);

</script>
</html>