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i18n.getMessage()

Gets the localized string for the specified message.

See the Internationalization page for a guide on using this function.

Syntax

browser.i18n.getMessage(
  messageName,  // string
  substitutions // optional any
)

Parameters

messageName

string. The name of the message, as specified in the messages.json file. If the message can't be found in messages.json:

  • Firefox returns "" and logs an error.
  • Chrome returns "" and does not log an error.
substitutions Optional

string or array of string. A single substitution string, or an array of substitution strings.

In Chrome, if you supply more than 9 substitution strings, getMessage() will return undefined.

Return value

string. Message localized for current locale.

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
getMessage 17
14["Throws an exception instead returning an empty string if the message does not exist.", "Expects substitutions to be strings, while other browsers allow any value which is then converted to a string."]
45Firefox 47 and earlier returns "??" instead of "" if the message is not found in _locales, bug 1258199 changed this act to match Chrome, landed on Firefox 48.
? 15 14 ? ? 48 ? 15 ?

Examples

Get the localized string for "messageContent", with target.url substituted:

let message = browser.i18n.getMessage("messageContent", target.url);
console.log(message);

This would work with a _locales/en/messages.json file containing:

{
  "messageContent": {
    "message": "You clicked $URL$.",
    "description": "Tells the user which link they clicked.",
    "placeholders": {
      "url" : {
        "content" : "$1",
        "example" : "https://developer.mozilla.org"
      }
    }
  }
}

If target.url is "https://developer.mozilla.org", then the value of message, in the "en" locale, would be:

"You clicked https://developer.mozilla.org."

Example extensions

Note: This API is based on Chromium's chrome.i18n API. This documentation is derived from i18n.json in the Chromium code.

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https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/i18n/getMessage