How to get the locale of a Firefox extension with Javascript

Question

I have spent lots of time trying to find a way to get the locale of Firefox extension within the extension's Javascript code. The closes I am general.useragent.locale, which I think holds the preferred localization, but Firefox's user language can be totally different.

Any idea?

Answer 1

When trying to query XUL packages, have a look at nsIXULChromeRegistry.getSelectedLocale(package) .

Sample (querying the locale for the global/toolkit package):

Components.classes["@mozilla.org/chrome/chrome-registry;1"]
  .getService(Components.interfaces.nsIXULChromeRegistry)
  .getSelectedLocale('global'); // e.g "en-US"

SDK add-ons could use the following to determine their own locale, although it should be noted that this API is marked "unstable".

require("sdk/l10n/core").locale

SDK add-ons may still use nsIXULChromeRegistry.getSelectedLocale(package) to query other add-ons or the browser via the chrome module.