# l20n.js
**Repository Path**: trusted-list/l20n.js
## Basic Information
- **Project Name**: l20n.js
- **Description**: A deprecated experiment. See Project Fluent instead.
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: https://projectfluent.org/
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 0
- **Created**: 2026-03-18
- **Last Updated**: 2026-04-18
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
L20n: Localization 2.0 (Deprecated)
===================================
__L20n.js has been deprecated and is no longer maintained. Please use
[Fluent][], the successor to L20n developed by the same team at Mozilla.
Fluent is a mature localization system currently used in Firefox and in many
other Mozilla projects.__
---
L20n is an opinionated localization library for the Web. It builds on top of
[Fluent][] which was designed to unleash the expressive power of the natural
language.
L20n.js is a good choice for websites which want to offer a best-in-class
translation experience for their users. L20n takes advantage of modern web
technologies to offer a fast and lean localization of HTML and JavaScript.
[Fluent]: http://projectfluent.org
How to use L20n
---------------
Include the following code in the `` section of your HTML:
```html
```
Use the `data-l10n-id` attribute on an HTML element to mark it as localizable.
```html
```
That's it! L20n will set up a `MutationObserver` and will make sure the
element is localized even if the DOM changes. See [docs/html][] for more
information.
[docs/html]: https://github.com/l20n/l20n.js/blob/master/docs/html.md
It is also possible to use L20n programmatically, for instance in order to
localize dynamic content. The API is exposed under `document.l10n`. Refer to
the [docs/][] directory for more details.
[docs/]: https://github.com/l20n/l20n.js/blob/master/docs/
Learn the FTL syntax
--------------------
L20n uses Project Fluent under the hood. FTL is a localization file format
used for describing translation resources. FTL stands for _Fluent Translation
List_.
FTL is designed to be simple to read, but at the same time allows to represent
complex concepts from natural languages like gender, plurals, conjugations,
and others.
hello-user = Hello, { $username }!
[Read the Fluent Syntax Guide][] in order to learn more about the syntax. If
you're a tool author you may be interested in the formal [EBNF grammar][].
[Read the Fluent Syntax Guide]: http://projectfluent.org/fluent/guide/
[EBNF grammar]: https://github.com/projectfluent/fluent/tree/master/spec