JavaScript for detecting browser language preference [duplicate]

Question

I have been trying to detect the browser language preference using JavaScript.

If I set the browser language in IE in Tools>Internet Options>General>Languages, how do I read this value using JavaScript?

Same problem for Firefox. I'm not able to detect the setting for tools>options>content>languages using navigator.language.

Using navigator.userLanguage , it detects the setting done thru Start>ControlPanel>RegionalandLanguageOptions>Regional Options tab.

I have tested with navigator.browserLanguage and navigator.systemLanguage but neither returns the value for the first setting(Tools>InternetOptions>General>Languages)

I found a link which discusses this in detail, but the question remains unanswered :(

Answer 1

I think the main problem here is that the browser settings don't actually affect the navigator.language property that is obtained via javascript.

What they do affect is the HTTP 'Accept-Language' header, but it appears this value is not available through javascript at all. (Probably why @anddoutoi states he can't find a reference for it that doesn't involve server side.)

I have coded a workaround: I've knocked up a google app engine script at http://ajaxhttpheaders.appspot.com that will return you the HTTP request headers via JSONP.

(Note: this is a hack only to be used if you do not have a back end available that can do this for you. In general you should not be making calls to third party hosted javascript files in your pages unless you have a very high level of trust in the host.)

I intend to leave it there in perpetuity so feel free to use it in your code.

Here's some example code (in jQuery) for how you might use it

$.ajax({      url: "http://ajaxhttpheaders.appspot.com",      dataType: 'jsonp',      success: function(headers) {         language = headers['Accept-Language'];         nowDoSomethingWithIt(language);     } }); 

Hope someone finds this useful.

Edit: I have written a small jQuery plugin on github that wraps this functionality: https://github.com/dansingerman/jQuery-Browser-Language

Edit 2: As requested here is the code that is running on AppEngine (super trivial really):

class MainPage(webapp.RequestHandler):     def get(self):         headers = self.request.headers         callback = self.request.get('callback')          if callback:           self.response.headers['Content-Type'] = 'application/javascript'           self.response.out.write(callback + "(")           self.response.out.write(headers)           self.response.out.write(")")         else:           self.response.headers['Content-Type'] = 'text/plain'           self.response.out.write("I need a callback=")  application = webapp.WSGIApplication(                                      [('/', MainPage)],                                      debug=False)  def main():     run_wsgi_app(application)  if __name__ == "__main__":     main() 

Edit3: Have open sourced the app engine code here: https://github.com/dansingerman/app-engine-headers

Answer 2

var language = window.navigator.userLanguage || window.navigator.language; alert(language); //works IE/SAFARI/CHROME/FF 

window.navigator.userLanguage is IE only and it's the language set in Windows Control Panel - Regional Options and NOT browser language, but you could suppose that a user using a machine with Window Regional settings set to France is probably a French user.

navigator.language is FireFox and all other browser.

Some language code: 'it' = italy, 'en-US' = english US, etc.

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As pointed out by rcoup and The WebMacheter in comments below, this workaround won't let you discriminate among English dialects when users are viewing website in browsers other than IE.

window.navigator.language (Chrome/FF/Safari) returns always browser language and not browser's preferred language, but: "it's pretty common for English speakers (gb, au, nz, etc) to have an en-us version of Firefox/Chrome/Safari." Hence window.navigator.language will still return en-US even if the user preferred language is en-GB.