Codice

  function chromeToFileUrl(url) {
      return Cc['@mozilla.org/chrome/chrome-registry;1']
      .getService(Ci.nsIChromeRegistry)
      .convertChromeURL(
          Cc['@mozilla.org/network/io-service;1']

          .getService(Ci.nsIIOService)
          .newURI(url, null, null)).spec;
  }