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

var detecting = browser.tabs.detectLanguage(
  tabId                   // optional integer
)

Parameters

tabIdOptional

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

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 the CLD2 README. 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.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Examples

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

function onLanguageDetected(lang) {
  console.log(`Language is: ${lang}`);
}
function onError(error) {
  console.log(`Error: ${error}`);
}
browser.browserAction.onClicked.addListener(function() {
  var detecting = browser.tabs.detectLanguage();
  detecting.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):

function onLanguageDetected(url, lang) {
  console.log(`Language in ${url} is: ${lang}`);
}
function onError(error) {
  console.log(`Error: ${error}`);
}
function detectLanguages(tabs) {
  for (tab of tabs) {
    var onFulfilled = onLanguageDetected.bind(null, tab.url);
    var detecting = browser.tabs.detectLanguage(tab.id);
    detecting.then(onFulfilled, onError);
  }
}
browser.browserAction.onClicked.addListener(function() {
  var querying = browser.tabs.query({});
  querying.then(detectLanguages, onError);
});

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