tabs.detectLanguage()

Detects the primary language of the content in a tab, using the Compact Language Detector (CLD).

This is an asynchronous function that returns a Promise.

Syntax

js
let detecting = browser.tabs.detectLanguage(
  tabId,                  // optional integer
  callback                // optional function
)

Parameters

tabId Optional

integer. Defaults to the active tab of the current window.

callback Optional

function. Currently, if a tabId is specified, this method uses this callback to return the results instead of returning a promise. The callback receives as its only input parameter a string containing the detected language code such as en or fr.

Return value

A Promise that will be fulfilled with a string representing an ISO language code such as en or fr. For a complete list of languages supported by this method, see kLanguageInfoTable. For an unknown language, "und" will be returned (but see bug 1288263). If any error occurs the promise will be rejected with an error message.

Examples

Detect and log the language of the active tab when the user clicks a browser action:

js
function onLanguageDetected(lang) {
  console.log(`Language is: ${lang}`);
}

function onError(error) {
  console.log(`Error: ${error}`);
}

browser.browserAction.onClicked.addListener(() => {
  browser.tabs.detectLanguage().then(onLanguageDetected, onError);
});

Detect and log the language of every open tab when the user clicks a browser action (note that this example requires the "tabs" permission):

js
function onLanguageDetected(url, lang) {
  console.log(`Language in ${url} is: ${lang}`);
}

function onError(error) {
  console.log(`Error: ${error}`);
}

function detectLanguages(tabs) {
  for (const tab of tabs) {
    browser.tabs
      .detectLanguage(tab.id)
      .then((lang) => onLanguageDetected(tab.url, lang), onError);
  }
}

browser.browserAction.onClicked.addListener(() => {
  browser.tabs.query({}).then(detectLanguages, onError);
});

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Firefox for Android
Safari on iOS
detectLanguage
Chrome – Full support
Chrome 5 (Release date: 2010-05-25)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 45 (Release date: 2016-03-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote
footnote Returns und (undefined language) for macOS versions before 11.
footnote Locale identifier will include the country code more often.
Firefox for Android – Full support
Firefox for Android 118 (Release date: 2023-09-26)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
See implementation notes.

Note: This API is based on Chromium's chrome.tabs API. This documentation is derived from tabs.json in the Chromium code.