lightweight jQuery plugin for providing internationalization to javascript from ‘.properties’ files
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About is a lightweight jQuery plugin for providing internationalization to javascript from ‘.properties’ files, just like in Java Resource Bundles. It loads and parses resource bundles (.properties) based on provided language and country codes (ISO-639 and ISO-3166) or language reported by browser.

Resource bundles are ‘.properties‘ files containing locale specific key-value pairs. The use of ‘.properties‘ files for translation is specially useful when sharing i18n files between Java and Javascript projects. This plugin loads the default file (eg, first and then locale specific files (, then, so that a default value is always available when there is no translation provided. Translation keys will be available to developer as javascript variables/functions (functions, if translated value contains substitutions (eg, {0}) or as a map.

This plugin was inspired on the Localisation assistance for jQuery from Keith Wood.

Latest Version



  • Use Java standard ‘.properties‘ files for translations
  • Use standard ISO-639 for language code and ISO-3166 for country code
  • Sequential loading of resource bundles from base language to user-specified/browser-specified so there is always a default value for an untranslated string (eg:,,
  • Use browser reported language if no language was specified
  • Placeholder substitution in resource bundle strings (eg, msg_hello = Hello {0}!!)
  • Suport for namespaces in keys (eg, = Hello!)
  • Support for multi-line property values
  • Resource bundle keys available as Javascript vars/functions or as a map
  • Support for namespacing.


This project was originally created by Nuno Miguel Correia Serra Fernandes and published on Google Code. In 2014 it has been migrated to Github which is now the official repository.

Since then, other great contributors joined the project (see Credits section below).

It has been used in various projects, including the WebRTC phone JSCommunicator (see the demo there to see jquery-i18n-properties in action), some Sakai Project tools, etc.


Take as an example the following .properties files:

# This line is ignored by the plugin
msg_hello = Hello
msg_world = World
msg_complex = Good morning {0}!

# We only provide a translation for the 'msg_hello' key
msg_hello = Bom dia

# We only provide a translation for the 'msg_hello' key
msg_hello = Olá

Now, suppose these files are located on the bundle/ folder. One can invoke the plugin like below:

// This will initialize the plugin 
// and show two dialog boxes: one with the text "Olá World"
// and other with the text "Good morning John!"{
    async: true,
    callback: function() {
        // We specified mode: 'both' so translated values will be
        // available as JS vars/functions and as a map

        // Accessing a simple value through the map
        // Accessing a value with placeholders through the map
        jQuery.i18n.prop('msg_complex', 'John');

        // Accessing a simple value through a JS variable
        alert(msg_hello +' '+ msg_world);
        // Accessing a value with placeholders through a JS function

This will initialize the plugin (loading bundle files and parsing them) and show a dialog box with the text “Olá World” and other with “Good morning John!”. The english word “World” is shown because we didn’t provide a translation for the msg_world key. Also notice that keys are available as a map and also as javascript variables (for simple strings) and javascript functions (for strings with placeholders for substitution).

Asynchronous Language File Loading

Synchronous Ajax has now been deprecated and will be removed at some point in the future, so web developers need to start thinking about writing their code as callbacks (

With this in mind ...

If you supply the flag 'async' on the settings and set it to true, all ajax calls are executed asynchronously and the supplied callback is called after the language files have all been downloaded and parsed. If you leave the flag off, or set it to false, the behaviour is as before: all the files are parsed synchronously and the callback is called at the end of the process.


Using the plugin

  1. Include it on your <head> section:
<script type="text/javascript" language="JavaScript"
  1. Initialize the plugin (minimal usage, will use language reported by browser), and access a translated value (assuming a key named ‘org.somekey‘ exists, it will be setup as a variable you can use directly in your Javascript):
  		name: 'Messages', 
  		callback: function(){ alert( org.somekey ); }

Additional requirement on Firefox

If using Firefox and a Tomcat webapp, you may get a syntax error in the Javascript console. The solution is to tell Tomcat the properties files should be interpreted as text/plain. To do this, add the following to your web.xml: <mime-mapping> <extension>properties</extension> <mime-type>text/plain</mime-type> </mime-mapping>

Building a minified JavaScript file

  1. Install the closure compiler tool:

    apt-get update && apt-get install closure-compiler

  2. Run it:

    closure-compiler --js \ --js_output_file


Option Description Notes
name Partial name (or names) of files representing resource bundles (eg, ‘Messages’ or ['Msg1','Msg2']). Defaults to 'Messages' Optional String or String[]
language ISO-639 Language code and, optionally, ISO-3166 country code (eg, ‘en’, ‘en_US’, ‘pt_BR’). If not specified, language reported by the browser will be used instead. Optional String
path Path to directory that contains ‘.properties‘ files to load. Optional String
namespace The namespace that you want your keys to be stored under. You'd access these keys like this: $[namespace][key]. Using a namespace minimises the chances of key clashes and overwrites. Optional String
mode Option to have resource bundle keys available as Javascript vars/functions OR as a map. The ‘map’ option is mandatory if your bundle keys contain Javascript Reserved Words. Possible options: ‘vars’ (default), ‘map’ or ‘both’. Optional String
debug Option to turn on console debug statement. Possible options: true or false. Optional boolean
cache Whether bundles should be cached by the browser, or forcibly reloaded on each page load. Defaults to false (i.e. forcibly reloaded). Optional boolean
encoding The encoding to request for bundles. Property file resource bundles are specified to be in ISO-8859-1 format. Defaults to UTF-8 for backward compatibility. Optional String
callback Callback function to be called uppon script execution completion. Optional function()

Copyright, Credits and License

Copyright © 2011 Nuno Miguel Correia Serra Fernandes (

Special thanks to great contributors:

Licensed under the MIT License.