Js translate. An Example to translate js into js file.

jsTranslate.js

/** Build your Js **/
alert(Translator.translate('My Text to translate'));
alert(Translator.translate('Another Text to translate'));

config.xml

<!-- Namespace/Module/etc/config.xml -->
<!-- Optional. Only if you want specify a csv file -->
<?xml version="1.0" encoding="utf-8"?>
<config>
  <frontend>
    <translate>
      <modules>
        <namespace_module>
          <files>
            <default>
              Namespace_Module.csv
            </default>
          </files>
        </namespace_module>
      </modules>
    </translate>
  </frontend>
</config>

jstranslator.xml

<!-- Namespace/Module/etc/jstranslator.xml -->
<?xml version="1.0" encoding="utf-8" ?>

<jstranslator>
    <my-unique-id translate="message" module="namespace_module">
        <message>My Text to translate</message>
    </my-unique-id>
    <another-unique-id translate="message" module="namespace_module">
        <message>Another Text to translate</message>
    </another-unique-id>
</jstranslator>

Namespace_Module.csv

/** app/local/fr_FR/Namespace_Module.csv **/
"My Text to translate","Mon texte à traduire"
"Another Text to translate","Un autre texte à traduire"