This feature is not on a current W3C standards track, but it is supported on the Firefox OS platform. Although implementations may change in the future and it is not supported widely across browsers, it is suitable for use in code dedicated to Firefox OS apps.


The language.code property returns the code of the currently active language and allows to change the language by setting the value to a new code.


var languageCode = navigator.mozL10n.language.code;


Returns the code of the currently active language.


navigator.mozL10n.ready(function() {
  console.log('The current language is ' + navigator.mozL10n.language.code);
navigator.mozL10n.once(function() {
  // change the current language to Traditional Chinese
  navigator.mozL10n.language.code = 'zh-TW';


Not part of any specification.

See also

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 Contributors to this page: chrisdavidmills, stasm
 Last updated by: chrisdavidmills,