diff --git a/extensions/firefox/.gitignore b/extensions/firefox/.gitignore
index 3eb92306c..08a23850c 100644
--- a/extensions/firefox/.gitignore
+++ b/extensions/firefox/.gitignore
@@ -1 +1,2 @@
 content/
+metadata.inc
diff --git a/extensions/firefox/components/PdfStreamConverter.js b/extensions/firefox/components/PdfStreamConverter.js
index f4b5b7712..af9cf41b8 100644
--- a/extensions/firefox/components/PdfStreamConverter.js
+++ b/extensions/firefox/components/PdfStreamConverter.js
@@ -58,6 +58,9 @@ ChromeActions.prototype = {
       return '{}';
     return application.prefs.getValue(EXT_PREFIX + '.database', '{}');
   },
+  getLocale: function() {
+    return application.prefs.getValue('general.useragent.locale', 'en-US');
+  },
   pdfBugEnabled: function() {
     return application.prefs.getValue(EXT_PREFIX + '.pdfBugEnabled', false);
   }
diff --git a/extensions/firefox/install.rdf b/extensions/firefox/install.rdf
index 0a0d813b2..d7eea9319 100644
--- a/extensions/firefox/install.rdf
+++ b/extensions/firefox/install.rdf
@@ -5,6 +5,7 @@
 
   <Description about="urn:mozilla:install-manifest">
     <em:id>uriloader@pdf.js</em:id>
+    <!-- PDFJS_LOCALIZED_METADATA -->
     <em:name>PDF Viewer</em:name>
     <em:version>PDFJSSCRIPT_VERSION</em:version>
     <em:targetApplication>
diff --git a/extensions/firefox/install.rdf.in b/extensions/firefox/install.rdf.in
index feab3e7ad..084d6dc2d 100644
--- a/extensions/firefox/install.rdf.in
+++ b/extensions/firefox/install.rdf.in
@@ -7,6 +7,7 @@
 
   <Description about="urn:mozilla:install-manifest">
     <em:id>uriloader@pdf.js</em:id>
+    <!-- PDFJS_LOCALIZED_METADATA -->
     <em:name>PDF Viewer</em:name>
     <em:version>PDFJSSCRIPT_VERSION</em:version>
     <em:targetApplication>
diff --git a/external/webL10n/README.md b/external/webL10n/README.md
new file mode 100644
index 000000000..52995522c
--- /dev/null
+++ b/external/webL10n/README.md
@@ -0,0 +1,3 @@
+The source code for the library can be found at
+
+  https://github.com/fabi1cazenave/webL10n
diff --git a/external/webL10n/l10n.js b/external/webL10n/l10n.js
new file mode 100644
index 000000000..f6c11c178
--- /dev/null
+++ b/external/webL10n/l10n.js
@@ -0,0 +1,322 @@
+/*  Copyright (c) 2011-2012 Fabien Cazenave, Mozilla.
+  *
+  * Permission is hereby granted, free of charge, to any person obtaining a copy
+  * of this software and associated documentation files (the "Software"), to
+  * deal in the Software without restriction, including without limitation the
+  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+  * sell copies of the Software, and to permit persons to whom the Software is
+  * furnished to do so, subject to the following conditions:
+  *
+  * The above copyright notice and this permission notice shall be included in
+  * all copies or substantial portions of the Software.
+  *
+  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+  * IN THE SOFTWARE.
+  */
+/*
+  Additional modifications for PDF.js project:
+    - Loading resources from <script type='application/l10n'>;
+    - Disabling language initialization on page loading;
+    - Add fallback argument to the translateString.
+*/
+'use strict';
+
+(function(window) {
+  var gL10nData = {};
+  var gTextData = '';
+  var gLanguage = '';
+
+  // parser
+
+  function evalString(text) {
+    return text.replace(/\\\\/g, '\\')
+               .replace(/\\n/g, '\n')
+               .replace(/\\r/g, '\r')
+               .replace(/\\t/g, '\t')
+               .replace(/\\b/g, '\b')
+               .replace(/\\f/g, '\f')
+               .replace(/\\{/g, '{')
+               .replace(/\\}/g, '}')
+               .replace(/\\"/g, '"')
+               .replace(/\\'/g, "'");
+  }
+
+  function parseProperties(text, lang) {
+    var reBlank = /^\s*|\s*$/;
+    var reComment = /^\s*#|^\s*$/;
+    var reSection = /^\s*\[(.*)\]\s*$/;
+    var reImport = /^\s*@import\s+url\((.*)\)\s*$/i;
+
+    // parse the *.properties file into an associative array
+    var currentLang = '*';
+    var supportedLang = [];
+    var skipLang = false;
+    var data = [];
+    var match = '';
+    var entries = text.replace(reBlank, '').split(/[\r\n]+/);
+    for (var i = 0; i < entries.length; i++) {
+      var line = entries[i];
+
+      // comment or blank line?
+      if (reComment.test(line))
+        continue;
+
+      // section start?
+      if (reSection.test(line)) {
+        match = reSection.exec(line);
+        currentLang = match[1];
+        skipLang = (currentLang != lang) && (currentLang != '*') &&
+          (currentLang != lang.substring(0, 2));
+        continue;
+      } else if (skipLang) {
+        continue;
+      }
+
+      // @import rule?
+      if (reImport.test(line)) {
+        match = reImport.exec(line);
+      }
+
+      // key-value pair
+      var tmp = line.split('=');
+      if (tmp.length > 1)
+        data[tmp[0]] = evalString(tmp[1]);
+    }
+
+    // find the attribute descriptions, if any
+    for (var key in data) {
+      var id, prop, index = key.lastIndexOf('.');
+      if (index > 0) { // attribute
+        id = key.substring(0, index);
+        prop = key.substr(index + 1);
+      } else { // textContent, could be innerHTML as well
+        id = key;
+        prop = 'textContent';
+      }
+      if (!gL10nData[id])
+        gL10nData[id] = {};
+      gL10nData[id][prop] = data[key];
+    }
+  }
+
+  function parse(text, lang) {
+    gTextData += text;
+    // we only support *.properties files at the moment
+    return parseProperties(text, lang);
+  }
+
+  // load and parse the specified resource file
+  function loadResource(href, lang, onSuccess, onFailure) {
+    var xhr = new XMLHttpRequest();
+    xhr.open('GET', href, true);
+    xhr.overrideMimeType('text/plain; charset=utf-8');
+    xhr.onreadystatechange = function() {
+      if (xhr.readyState == 4) {
+        if (xhr.status == 200 || xhr.status == 0) {
+          parse(xhr.responseText, lang);
+          if (onSuccess)
+            onSuccess();
+        } else {
+          if (onFailure)
+            onFailure();
+        }
+      }
+    };
+    xhr.send(null);
+  }
+
+  // load and parse all resources for the specified locale
+  function loadLocale(lang, callback) {
+    clear();
+
+    // check all <link type="application/l10n" href="..." /> nodes
+    // and load the resource files
+    var langLinks = document.querySelectorAll('link[type="application/l10n"]');
+    var langLinksCount = langLinks.length;
+    var langScripts = document.querySelectorAll('script[type="application/l10n"]');
+    var langScriptCount = langScripts.length;
+    var langCount = langLinksCount + langScriptCount;
+
+    // start the callback when all resources are loaded
+    var onResourceLoaded = null;
+    var gResourceCount = 0;
+    onResourceLoaded = function() {
+      gResourceCount++;
+      if (gResourceCount >= langCount) {
+        // execute the [optional] callback
+        if (callback)
+          callback();
+        // fire a 'localized' DOM event
+        var evtObject = document.createEvent('Event');
+        evtObject.initEvent('localized', false, false);
+        evtObject.language = lang;
+        window.dispatchEvent(evtObject);
+      }
+    }
+
+    // load all resource files
+    function l10nResourceLink(link) {
+      var href = link.href;
+      var type = link.type;
+      this.load = function(lang, callback) {
+        var applied = lang;
+        loadResource(href, lang, callback, function() {
+          console.warn(href + ' not found.');
+          applied = '';
+        });
+        return applied; // return lang if found, an empty string if not found
+      };
+    }
+
+    gLanguage = lang;
+    for (var i = 0; i < langLinksCount; i++) {
+      var resource = new l10nResourceLink(langLinks[i]);
+      var rv = resource.load(lang, onResourceLoaded);
+      if (rv != lang) // lang not found, used default resource instead
+        gLanguage = '';
+    }
+    for (var i = 0; i < langScriptCount; i++) {
+      var scriptText = langScripts[i].text;
+      parse(scriptText, lang);
+      onResourceLoaded();
+    }
+  }
+
+  // fetch an l10n object, warn if not found
+  function getL10nData(key) {
+    var data = gL10nData[key];
+    if (!data)
+      console.warn('[l10n] #' + key + ' missing for [' + gLanguage + ']');
+    return data;
+  }
+
+  // replace {{arguments}} with their values
+  function substArguments(str, args) {
+    var reArgs = /\{\{\s*([a-zA-Z\.]+)\s*\}\}/;
+    var match = reArgs.exec(str);
+    while (match) {
+      if (!match || match.length < 2)
+        return str; // argument key not found
+
+      var arg = match[1];
+      var sub = '';
+      if (arg in args) {
+        sub = args[arg];
+      } else if (arg in gL10nData) {
+        sub = gL10nData[arg].textContent;
+      } else {
+        console.warn('[l10n] could not find argument {{' + arg + '}}');
+        return str;
+      }
+
+      str = str.substring(0, match.index) + sub +
+            str.substr(match.index + match[0].length);
+      match = reArgs.exec(str);
+    }
+    return str;
+  }
+
+  // translate a string
+  function translateString(key, args, fallback) {
+    var data = getL10nData(key);
+    if (!data && fallback)
+      data = {textContent: fallback};
+    if (!data)
+      return '{{' + key + '}}';
+    return substArguments(data.textContent, args);
+  }
+
+  // translate an HTML element
+  function translateElement(element) {
+    if (!element || !element.dataset)
+      return;
+
+    // get the related l10n object
+    var key = element.dataset.l10nId;
+    var data = getL10nData(key);
+    if (!data)
+      return;
+
+    // get arguments (if any)
+    // TODO: more flexible parser?
+    var args;
+    if (element.dataset.l10nArgs) try {
+      args = JSON.parse(element.dataset.l10nArgs);
+    } catch (e) {
+      console.warn('[l10n] could not parse arguments for #' + key + '');
+    }
+
+    // translate element
+    // TODO: security check?
+    for (var k in data)
+      element[k] = substArguments(data[k], args);
+  }
+
+  // translate an HTML subtree
+  function translateFragment(element) {
+    element = element || document.querySelector('html');
+
+    // check all translatable children (= w/ a `data-l10n-id' attribute)
+    var children = element.querySelectorAll('*[data-l10n-id]');
+    var elementCount = children.length;
+    for (var i = 0; i < elementCount; i++)
+      translateElement(children[i]);
+
+    // translate element itself if necessary
+    if (element.dataset.l10nId)
+      translateElement(element);
+  }
+
+  // clear all l10n data
+  function clear() {
+    gL10nData = {};
+    gTextData = '';
+    gLanguage = '';
+  }
+
+  /*
+  // load the default locale on startup
+  window.addEventListener('DOMContentLoaded', function() {
+    var lang = navigator.language;
+    if (navigator.mozSettings) {
+      var req = navigator.mozSettings.getLock().get('language.current');
+      req.onsuccess = function() {
+        loadLocale(req.result['language.current'] || lang, translateFragment);
+      };
+      req.onerror = function() {
+        loadLocale(lang, translateFragment);
+      };
+    } else {
+      loadLocale(lang, translateFragment);
+    }
+  });
+  */
+
+  // Public API
+  document.mozL10n = {
+    // get a localized string
+    get: translateString,
+
+    // get|set the document language and direction
+    get language() {
+      return {
+        // get|set the document language (ISO-639-1)
+        get code() { return gLanguage; },
+        set code(lang) { loadLocale(lang, translateFragment); },
+
+        // get the direction (ltr|rtl) of the current language
+        get direction() {
+          // http://www.w3.org/International/questions/qa-scripts
+          // Arabic, Hebrew, Farsi, Pashto, Urdu
+          var rtlList = ['ar', 'he', 'fa', 'ps', 'ur'];
+          return (rtlList.indexOf(gLanguage) >= 0) ? 'rtl' : 'ltr';
+        }
+      };
+    }
+  };
+})(this);
diff --git a/l10n/ar/metadata.inc b/l10n/ar/metadata.inc
new file mode 100644
index 000000000..f1a7106a6
--- /dev/null
+++ b/l10n/ar/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>ar</em:locale>
+        <em:name>عارض PDF</em:name>
+        <em:description>يستخدم HTML5 لعرض ملفات PDF مباشره من خلال Firefox.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/ar/viewer.properties b/l10n/ar/viewer.properties
new file mode 100644
index 000000000..57363c4b0
--- /dev/null
+++ b/l10n/ar/viewer.properties
@@ -0,0 +1,31 @@
+bookmark.title=النافذه الحالية (نسخ أو فتح نافذة جديدة)
+previous.title=السابق
+next.title=التالي
+print.title=طباعة
+download.title=تحميل
+zoom_out.title=التصغير
+zoom_in.title=تكبير
+error_more_info=مزيد من المعلومات
+error_less_info=معلومات أقل
+error_close=أغلق
+error_build=PDF.JS بناء: {{build}}
+error_message=رسالة: {{message}}
+error_stack=المكدس: {{stack}}
+error_file=ملف: {{file}}
+error_line=سطر: {{line}}
+page_scale_width=عرض الصفحه
+page_scale_fit=تحجيم الصفحه
+page_scale_auto=تكبير تلقائي
+page_scale_actual=الحجم الفعلي
+toggle_slider.title=تبديل المتزلج
+thumbs.title=اظهار الصور المصغرة
+outline.title=عرض مخطط الوثيقه
+loading=تحميل ... {{percent}}٪ 
+loading_error_indicator=خطأ
+loading_error=حدث خطأ أثناء تحميل وثيقه بي دي اف
+rendering_error=حدث خطأ اثناء رسم الصفحه
+page_label=الصفحة:
+page_of=من {{pageCount}}
+no_outline=لايوجد مخطط
+open_file.title=فتح ملف
+text_annotation_type=[{{type}} ملاحظة]
diff --git a/l10n/da-DK/metadata.inc b/l10n/da-DK/metadata.inc
new file mode 100644
index 000000000..f153cceb7
--- /dev/null
+++ b/l10n/da-DK/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>da-DK</em:locale>
+        <em:name>PDF Viewer</em:name>
+        <em:description>Benytter HTML5 til at vise PDF-filer direkte i Firefox.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/da-DK/viewer.properties b/l10n/da-DK/viewer.properties
new file mode 100644
index 000000000..6d208db70
--- /dev/null
+++ b/l10n/da-DK/viewer.properties
@@ -0,0 +1,31 @@
+bookmark.title=Aktuel visning (kopier eller åbn i et nyt vindue)
+previous.title=Forrige
+next.title=Næste
+print.title=Udskriv
+download.title=Hent
+zoom_out.title=Zoom ud
+zoom_in.title=Zoom ind
+error_more_info=Mere information
+error_less_info=Mindre information
+error_close=Luk
+error_build=PDF.JS Build: {{build}}
+error_message=Besked: {{message}}
+error_stack=Stak: {{stack}}
+error_file=Fil: {{file}}
+error_line=Linje: {{line}}
+page_scale_width=Sidebredde
+page_scale_fit=Helside
+page_scale_auto=Automatisk zoom
+page_scale_actual=Faktisk størrelse
+toggle_slider.title=Skift Slider
+thumbs.title=Vis thumbnails
+outline.title=Vis dokumentoversigt
+loading=Indlæser... {{percent}}%
+loading_error_indicator=Fejl
+loading_error=Der skete en fejl under indlæsningen af PDF-filen
+rendering_error=Der skete en fejl under gengivelsen af PDF-filen
+page_label=Side:
+page_of=af {{pageCount}}
+no_outline=Ingen dokumentoversigt tilgængelig
+open_file.title=Åbn fil
+text_annotation_type=[{{type}} Kommentar]
diff --git a/l10n/de-DE/metadata.inc b/l10n/de-DE/metadata.inc
new file mode 100644
index 000000000..f6e912942
--- /dev/null
+++ b/l10n/de-DE/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>de-DE</em:locale>
+        <em:name>PDF Viewer</em:name>
+        <em:description>Nutzt HTML5 um PDFs direkt in Firefox anzuzeigen.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/de-DE/viewer.properties b/l10n/de-DE/viewer.properties
new file mode 100644
index 000000000..a1d5c36c5
--- /dev/null
+++ b/l10n/de-DE/viewer.properties
@@ -0,0 +1,31 @@
+bookmark.title=Aktuelle Ansicht (Kopieren oder in einem neuen Fenster öffnen)
+previous.title=Zurück
+next.title=Vor
+print.title=Drucken
+download.title=Runterladen
+zoom_out.title=Verkleinern
+zoom_in.title=Vergrößern
+error_more_info=Mehr Info
+error_less_info=Weniger Info
+error_close=Schließen
+error_build=PDF.JS Build: {{build}}
+error_message=Nachricht: {{message}}
+error_stack=Stack: {{stack}}
+error_file=Datei: {{file}}
+error_line=Zeile: {{line}}
+page_scale_width=Seitenbreite
+page_scale_fit=Ganze Seite
+page_scale_auto=Automatisch
+page_scale_actual=Originalgröße
+toggle_slider.title=Thumbnails ein-/ausblenden
+thumbs.title=Zeige Thumbnails
+outline.title=Zeige Inhaltsverzeichnis
+loading=Lade... {{percent}}%
+loading_error_indicator=Fehler
+loading_error=Das PDF konnte nicht geladen werden.
+rendering_error=Das PDF konnte nicht angezeigt werden.
+page_label=Seite:
+page_of=von {{pageCount}}
+no_outline=Kein Inhaltsverzeichnis verfügbar
+open_file.title=Öffne Datei
+text_annotation_type=[{{type}} Annotation]
diff --git a/l10n/en-US/metadata.inc b/l10n/en-US/metadata.inc
new file mode 100644
index 000000000..8d9d94b04
--- /dev/null
+++ b/l10n/en-US/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>en-US</em:locale>
+        <em:name>PDF Viewer</em:name>
+        <em:description>Uses HTML5 to display PDF files directly in Firefox.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/en-US/viewer.properties b/l10n/en-US/viewer.properties
new file mode 100644
index 000000000..ed632b17a
--- /dev/null
+++ b/l10n/en-US/viewer.properties
@@ -0,0 +1,42 @@
+bookmark.title=Current view (copy or open in new window)
+previous.title=Previous Page
+next.title=Next Page
+print.title=Print
+download.title=Download
+zoom_out.title=Zoom Out
+zoom_in.title=Zoom In
+error_more_info=More Information
+error_less_info=Less Information
+error_close=Close
+error_build=PDF.JS Build: {{build}}
+error_message=Message: {{message}}
+error_stack=Stack: {{stack}}
+error_file=File: {{file}}
+error_line=Line: {{line}}
+page_scale_width=Page Width
+page_scale_fit=Page Fit
+page_scale_auto=Automatic Zoom
+page_scale_actual=Actual Size
+toggle_slider.title=Toggle Slider
+thumbs.title=Show Thumbnails
+outline.title=Show Document Outline
+loading=Loading... {{percent}}%
+loading_error_indicator=Error
+loading_error=An error occurred while loading the PDF.
+rendering_error=An error occurred while rendering the page.
+page_label=Page:
+page_of=of {{pageCount}}
+no_outline=No Outline Available
+open_file.title=Open File
+text_annotation_type=[{{type}} Annotation]
+toggle_slider_label=Toggle Slider
+thumbs_label=Thumbnails
+outline_label=Document Outline
+bookmark_label=Current View
+previous_label=Previous
+next_label=Next
+print_label=Print
+download_label=Download
+zoom_out_label=Zoom Out
+zoom_in_label=Zoom In
+zoom.title=Zoom
diff --git a/l10n/it/metadata.inc b/l10n/it/metadata.inc
new file mode 100644
index 000000000..e09d807b1
--- /dev/null
+++ b/l10n/it/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>it</em:locale>
+        <em:name>PDF Viewer</em:name>
+        <em:description>Usa HTML5 per visualizzare i file PDF direttamente in Firefox.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/it/viewer.properties b/l10n/it/viewer.properties
new file mode 100644
index 000000000..86e16bf6d
--- /dev/null
+++ b/l10n/it/viewer.properties
@@ -0,0 +1,31 @@
+bookmark.title=Visualizzazione corrente (copia o apri in una nuova finestra)
+previous.title=Precedente
+next.title=Successiva
+print.title=Stampa
+download.title=Download
+zoom_out.title=Riduci Zoom
+zoom_in.title=Aumenta Zoom
+error_more_info=Pi� Informazioni
+error_less_info=Meno Informazioni
+error_close=Chiudi
+error_build=PDF.JS Build: {{build}}
+error_message=Messaggio: {{message}}
+error_stack=Stack: {{stack}}
+error_file=File: {{file}}
+error_line=Linea: {{line}}
+page_scale_width=Adatta alla Larghezza
+page_scale_fit=Adatta alla Pagina
+page_scale_auto=Zoom Automatico
+page_scale_actual=Dimensione Attuale
+toggle_slider.title=Visualizza Riquadro Laterale
+thumbs.title=Mostra Miniature
+outline.title=Mostra Indice Documento
+loading=Caricamento... {{percent}}%
+loading_error_indicator=Errore
+loading_error=� accaduto un errore durante il caricamento del PDF.
+rendering_error=� accaduto un errore durante il rendering della pagina.
+page_label=Pagina:
+page_of=di {{pageCount}}
+no_outline=Nessun Indice Disponibile
+open_file.title=Apri File
+text_annotation_type=[{{type}} Annotazione]
diff --git a/l10n/pt-BR/metadata.inc b/l10n/pt-BR/metadata.inc
new file mode 100644
index 000000000..179af8b31
--- /dev/null
+++ b/l10n/pt-BR/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>pt-BR</em:locale>
+        <em:name>PDF Viewer</em:name>
+        <em:description>Aprensenta PDFs no browser usando a tecnologia HTML5.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/pt-BR/viewer.properties b/l10n/pt-BR/viewer.properties
new file mode 100644
index 000000000..0d268e1d5
--- /dev/null
+++ b/l10n/pt-BR/viewer.properties
@@ -0,0 +1,31 @@
+bookmark.title=Marcar posição atual (bookmark)
+previous.title=Página anterior
+next.title=Próxima página
+print.title=Imprimir
+download.title=Baixar arquivo
+zoom_out.title=Diminuir Zoom
+zoom_in.title=Aumentar Zoom
+error_more_info=Mais informações
+error_less_info=Menos informações
+error_close=Fechar
+error_build=PDF.JS Versão: {{build}}
+error_message=Mensagem: {{message}}
+error_stack=Pilha: {{stack}}
+error_file=Arquivo: {{file}}
+error_line=Linha: {{line}}
+page_scale_width=Largura da página
+page_scale_fit=Página inteira
+page_scale_auto=Zoom automático
+page_scale_actual=Tamanho original
+toggle_slider.title=Abrir/fechar aba lateral
+thumbs.title=Mostrar miniaturas
+outline.title=Mostrar índice
+loading=Carregando... {{percent}}%
+loading_error_indicator=Erro
+loading_error=Um erro ocorreu ao carregar o arquivo.
+rendering_error=Um erro ocorreu ao apresentar a página.
+page_label=Página:
+page_of=de {{pageCount}}
+no_outline=Índice não disponível
+open_file.title=Abrir arquivo
+text_annotation_type=[{{type}} Anotações]
diff --git a/l10n/ru/metadata.inc b/l10n/ru/metadata.inc
new file mode 100644
index 000000000..410814c5d
--- /dev/null
+++ b/l10n/ru/metadata.inc
@@ -0,0 +1,8 @@
+    <em:localized>
+      <Description>
+        <em:locale>ru</em:locale>
+        <em:name>PDF Viewer</em:name>
+        <em:description>Показывает файлы PDF непосредственно в Firefox используя HTML5.</em:description>
+      </Description>
+    </em:localized>
+
diff --git a/l10n/ru/viewer.properties b/l10n/ru/viewer.properties
new file mode 100644
index 000000000..a946cde98
--- /dev/null
+++ b/l10n/ru/viewer.properties
@@ -0,0 +1,42 @@
+bookmark.title=Ссылка на текущий вид (скопировать или открыть в новом окне) 
+previous.title=Предыдущая страница
+next.title=Следующая страница
+print.title=Печать
+download.title=Загрузить
+zoom_out.title=Уменьшить
+zoom_in.title=Увеличить
+error_more_info=Детали
+error_less_info=Скрыть детали
+error_close=Закрыть
+error_build=PDF.JS компиляция: {{build}}
+error_message=Сообщение: {{message}}
+error_stack=Стeк: {{stack}}
+error_file=Файл: {{file}}
+error_line=Строка: {{line}}
+page_scale_width=По ширине страницы
+page_scale_fit=Во всю страницу
+page_scale_auto=Авто
+page_scale_actual=Настоящий размер
+toggle_slider.title=Открыть/закрыть вспомогательную панель
+thumbs.title=Показать уменьшенные изображения
+outline.title=Показать содержание документа
+loading=Загрузка... {{percent}}%
+loading_error_indicator=Ошибка
+loading_error=Произошла ошибка во время загрузки PDF.
+rendering_error=Произошла ошибка во время создания страницы.
+page_label=Страница:
+page_of=из {{pageCount}}
+no_outline=Содержание не доступно
+open_file.title=Открыть файл
+text_annotation_type=[Аннотация {{type}}]
+toggle_slider_label=Вспомогательная панель
+thumbs_label=Уменьшенные изображения
+outline_label=Содержание документа
+bookmark_label=Текущий вид
+previous_label=Предыдущая
+next_label=Следующая
+print_label=Печать
+download_label=Загрузить
+zoom_out_label=Уменьшить
+zoom_in_label=Увеличить
+zoom.title=Масштаб
diff --git a/l10n/xx/viewer.properties b/l10n/xx/viewer.properties
new file mode 100644
index 000000000..5b9971d0b
--- /dev/null
+++ b/l10n/xx/viewer.properties
@@ -0,0 +1,42 @@
+bookmark.title=<<<_¢ȗггεпţ ṿiεẂ (¢OÞӳ Oг OÞεп iп пεẂ ẂiпÐOẂ)_>>>
+previous.title=<<<_ÞгεṿiOȗ§ Þãģε_>>>
+next.title=<<<_пεӾţ Þãģε_>>>
+print.title=<<<_Þгiпţ_>>>
+download.title=<<<_ÐOẂпḻOãÐ_>>>
+zoom_out.title=<<<_ƩOOм Oȗţ_>>>
+zoom_in.title=<<<_ƩOOм iп_>>>
+error_more_info=<<<_мOгε iп£OгмãţiOп_>>>
+error_less_info=<<<_ḻ姧 iп£OгмãţiOп_>>>
+error_close=<<<_¢ḻO§ε_>>>
+error_build=<<<_ÞУ.ʃ§ ьȗiḻÐ: {{build}}_>>>
+error_message=<<<_м姧ãģε: {{message}}_>>>
+error_stack=<<<_§ţã¢қ: {{stack}}_>>>
+error_file=<<<_£iḻε: {{file}}_>>>
+error_line=<<<_ḻiпε: {{line}}_>>>
+page_scale_width=<<<_Þãģε ẂiÐţН_>>>
+page_scale_fit=<<<_Þãģε £iţ_>>>
+page_scale_auto=<<<_ãȗţOмãţi¢ ƩOOм_>>>
+page_scale_actual=<<<_ã¢ţȗãḻ §iƩε_>>>
+toggle_slider.title=<<<_ţOģģḻε §ḻiÐεг_>>>
+thumbs.title=<<<_§НOẂ ţНȗмьпãiḻ§_>>>
+outline.title=<<<_§НOẂ ÐO¢ȗмεпţ Oȗţḻiпε_>>>
+loading=<<<_ḻOãÐiпģ... {{percent}}%_>>>
+loading_error_indicator=<<<_εггOг_>>>
+loading_error=<<<_ãп εггOг O¢¢ȗггεÐ ẂНiḻε ḻOãÐiпģ ţНε ÞУ._>>>
+rendering_error=<<<_ãп εггOг O¢¢ȗггεÐ ẂНiḻε гεпÐεгiпģ ţНε Þãģε._>>>
+page_label=Þãģε:
+page_of=<<<_O£ {{pageCount}}_>>>
+no_outline=<<<_пO Oȗţḻiпε ãṿãiḻãьḻε_>>>
+open_file.title=<<<_OÞεп £iḻε_>>>
+text_annotation_type=<<<_[{{type}} ãппOţãţiOп]_>>>
+toggle_slider_label=<<<_ţOģģḻε §ḻiÐεг_>>>
+thumbs_label=<<<_ţНȗмьпãiḻ§_>>>
+outline_label=<<<_ÐO¢ȗмεпţ Oȗţḻiпε_>>>
+bookmark_label=<<<_¢ȗггεпţ ṿiεẂ_>>>
+previous_label=<<<_ÞгεṿiOȗ§_>>>
+next_label=<<<_пεӾţ_>>>
+print_label=<<<_Þгiпţ_>>>
+download_label=<<<_ÐOẂпḻOãÐ_>>>
+zoom_out_label=<<<_ƩOOм Oȗţ_>>>
+zoom_in_label=<<<_ƩOOм iп_>>>
+zoom.title=<<<_ƩOOм_>>>
diff --git a/make.js b/make.js
index b28682053..3bb70dc91 100755
--- a/make.js
+++ b/make.js
@@ -33,6 +33,7 @@ target.all = function() {
 //
 target.web = function() {
   target.production();
+  target.locale();
   target.extension();
   target.pagesrepo();
 
@@ -40,8 +41,13 @@ target.web = function() {
   echo();
   echo('### Creating web site');
 
+  var GH_PAGES_SRC_FILES = [
+    'web/*',
+    'external/webL10n/l10n.js'
+  ];
+
   cp(BUILD_TARGET, GH_PAGES_DIR + BUILD_TARGET);
-  cp('-R', 'web/*', GH_PAGES_DIR + '/web');
+  cp('-R', GH_PAGES_SRC_FILES, GH_PAGES_DIR + '/web');
   cp(FIREFOX_BUILD_DIR + '/*.xpi', FIREFOX_BUILD_DIR + '/*.rdf',
     GH_PAGES_DIR + EXTENSION_SRC_DIR + 'firefox/');
   cp(GH_PAGES_DIR + '/web/index.html.template', GH_PAGES_DIR + '/index.html');
@@ -56,6 +62,52 @@ target.web = function() {
     " and issue 'git commit' to push changes.");
 };
 
+//
+// make locale
+// Creates localized resources for the viewer and extension.
+//
+target.locale = function() {
+  var L10N_PATH = 'l10n';
+  var METADATA_OUTPUT = 'extensions/firefox/metadata.inc';
+  var VIEWER_OUTPUT = 'web/locale.properties';
+  var DEFAULT_LOCALE = 'en-US';
+
+  cd(ROOT_DIR);
+  echo();
+  echo('### Building localization files');
+
+  var subfolders = ls(L10N_PATH);
+  subfolders.sort();
+  var metadataContent = '';
+  var viewerOutput = '';
+  for (var i = 0; i < subfolders.length; i++) {
+    var locale = subfolders[i];
+    var path = L10N_PATH + '/' + locale;
+    if (!test('-d', path))
+      continue;
+
+    if (!/^[a-z][a-z](-[A-Z][A-Z])?$/.test(locale)) {
+      echo('Skipping invalid locale: ' + locale);
+      continue;
+    }
+
+    if (test('-f', path + '/viewer.properties')) {
+      var properties = cat(path + '/viewer.properties');
+      if (locale == DEFAULT_LOCALE)
+        viewerOutput = '[*]\n' + properties + '\n' + viewerOutput;
+      else
+        viewerOutput = viewerOutput + '[' + locale + ']\n' + properties + '\n';
+    }
+
+    if (test('-f', path + '/metadata.inc')) {
+      var metadata = cat(path + '/metadata.inc');
+      metadataContent += metadata;
+    }
+  }
+  viewerOutput.to(VIEWER_OUTPUT);
+  metadataContent.to(METADATA_OUTPUT);
+};
+
 //
 // make production
 // Creates production output (pdf.js, and corresponding changes to web/ files)
@@ -175,6 +227,8 @@ var EXTENSION_WEB_FILES =
        'web/viewer.css',
        'web/viewer.js',
        'web/viewer.html',
+       'external/webL10n/l10n.js',
+       'web/locale.properties',
        'web/viewer-production.html'],
     EXTENSION_BASE_VERSION = 'f0f0418a9c6637981fe1182b9212c2d592774c7d',
     EXTENSION_VERSION_PREFIX = '0.3.',
@@ -245,6 +299,8 @@ target.firefox = function() {
       FIREFOX_EXTENSION_NAME = 'pdf.js.xpi',
       FIREFOX_AMO_EXTENSION_NAME = 'pdf.js.amo.xpi';
 
+  var LOCALE_CONTENT = cat('web/locale.properties');
+
   target.production();
   target.buildnumber();
   cd(ROOT_DIR);
@@ -271,6 +327,7 @@ target.firefox = function() {
   // Modify the viewer so it does all the extension-only stuff.
   cd(FIREFOX_BUILD_CONTENT_DIR + '/web');
   sed('-i', /.*PDFJSSCRIPT_INCLUDE_BUNDLE.*\n/, cat(ROOT_DIR + BUILD_TARGET), 'viewer-snippet-firefox-extension.html');
+  sed('-i', /.*PDFJSSCRIPT_LOCALE_DATA.*\n/, LOCALE_CONTENT, 'viewer-snippet-firefox-extension.html');
   sed('-i', /.*PDFJSSCRIPT_REMOVE_CORE.*\n/g, '', 'viewer.html');
   sed('-i', /.*PDFJSSCRIPT_REMOVE_FIREFOX_EXTENSION.*\n/g, '', 'viewer.html');
   sed('-i', /.*PDFJSSCRIPT_INCLUDE_FIREFOX_EXTENSION.*\n/, cat('viewer-snippet-firefox-extension.html'), 'viewer.html');
@@ -278,6 +335,8 @@ target.firefox = function() {
 
   // We don't need pdf.js anymore since its inlined
   rm('-Rf', FIREFOX_BUILD_CONTENT_DIR + BUILD_DIR);
+  rm(FIREFOX_BUILD_CONTENT_DIR + '/web/viewer-snippet-firefox-extension.html');
+  rm(FIREFOX_BUILD_CONTENT_DIR + '/web/locale.properties');
   // Remove '.DS_Store' and other hidden files
   find(FIREFOX_BUILD_DIR).forEach(function(file) {
     if (file.match(/^\./))
@@ -290,6 +349,11 @@ target.firefox = function() {
   sed('-i', /PDFJSSCRIPT_VERSION/, EXTENSION_VERSION, FIREFOX_BUILD_DIR + '/install.rdf.in');
   sed('-i', /PDFJSSCRIPT_VERSION/, EXTENSION_VERSION, FIREFOX_BUILD_DIR + '/README.mozilla');
 
+  // Update localized metadata
+  var localizedMetadata = cat(EXTENSION_SRC_DIR + '/firefox/metadata.inc');
+  sed('-i', /.*PDFJS_LOCALIZED_METADATA.*\n/, localizedMetadata, FIREFOX_BUILD_DIR + '/install.rdf');
+  sed('-i', /.*PDFJS_LOCALIZED_METADATA.*\n/, localizedMetadata, FIREFOX_BUILD_DIR + '/install.rdf.in');
+
   // Create the xpi
   cd(FIREFOX_BUILD_DIR);
   exec('zip -r ' + FIREFOX_EXTENSION_NAME + ' ' + FIREFOX_EXTENSION_FILES.join(' '));
diff --git a/test/test.py b/test/test.py
index d5b473107..5dcc77298 100644
--- a/test/test.py
+++ b/test/test.py
@@ -73,7 +73,8 @@ MIMEs = {
     '.gif': 'image/gif',
     '.ico': 'image/x-icon',
     '.png': 'image/png',
-    '.log': 'text/plain'
+    '.log': 'text/plain',
+    '.properties': 'text/plain'
 }
 
 class State:
diff --git a/web/.gitignore b/web/.gitignore
index 2c0f5df71..588e0e724 100644
--- a/web/.gitignore
+++ b/web/.gitignore
@@ -1 +1,2 @@
 viewer-production.html
+locale.properties
diff --git a/web/images/toolbarButton-pageDown-rtl.png b/web/images/toolbarButton-pageDown-rtl.png
new file mode 100644
index 000000000..c0051f8f0
Binary files /dev/null and b/web/images/toolbarButton-pageDown-rtl.png differ
diff --git a/web/images/toolbarButton-pageUp-rtl.png b/web/images/toolbarButton-pageUp-rtl.png
new file mode 100644
index 000000000..0d49d8e95
Binary files /dev/null and b/web/images/toolbarButton-pageUp-rtl.png differ
diff --git a/web/viewer-snippet-firefox-extension.html b/web/viewer-snippet-firefox-extension.html
index a3d3502a8..57d7875eb 100644
--- a/web/viewer-snippet-firefox-extension.html
+++ b/web/viewer-snippet-firefox-extension.html
@@ -1,5 +1,9 @@
 <!-- This snippet is used in firefox extension, see Makefile -->
 <base href="resource://pdf.js/web/" />
+<script type="application/l10n">
+<!-- PDFJSSCRIPT_LOCALE_DATA -->
+</script>
+<script type="text/javascript" src="l10n.js"></script>
 <script type="text/javascript" id="PDFJS_SCRIPT_TAG">
 <!--
 // pdf.js is inlined here because resource:// urls won't work
diff --git a/web/viewer-snippet.html b/web/viewer-snippet.html
index 6b0c8821b..3d535169e 100644
--- a/web/viewer-snippet.html
+++ b/web/viewer-snippet.html
@@ -1,4 +1,6 @@
 <!-- This snippet is used in production, see Makefile -->
+<link rel="resource" type="application/l10n" href="locale.properties"/>
+<script type="text/javascript" src="l10n.js"></script>
 <script type="text/javascript" src="../build/pdf.js"></script>
 <script type="text/javascript">
   // This specifies the location of the pdf.js file.
diff --git a/web/viewer.css b/web/viewer.css
index c50767905..7b0ce0344 100644
--- a/web/viewer.css
+++ b/web/viewer.css
@@ -22,16 +22,26 @@ body {
 }
 
 /* outer/inner center provides horizontal center */
-.outerCenter {
+html[dir='ltr'] .outerCenter {
   float: right;
   position: relative;
   right: 50%;
 }
-.innerCenter {
+html[dir='rtl'] .outerCenter {
+  float: left;
+  position: relative;
+  left: 50%;
+}
+html[dir='ltr'] .innerCenter {
   float: right;
   position: relative;
   right: -50%;
 }
+html[dir='rtl'] .innerCenter {
+  float: left;
+  position: relative;
+  left: -50%;
+}
 
 #outerContainer {
   width: 100%;
@@ -42,23 +52,34 @@ body {
   position: absolute;
   top: 0;
   bottom: 0;
-  left: -200px;
   width: 200px;
   visibility: hidden;
-  -moz-transition-property: left;
   -moz-transition-duration: 200ms;
   -moz-transition-timing-function: ease;
-  -webkit-transition-property: left;
   -webkit-transition-duration: 200ms;
   -webkit-transition-timing-function: ease;
 }
-#outerContainer.sidebarMoving > #sidebarContainer {
-  visibility: visible;
+html[dir='ltr'] #sidebarContainer {
+  -moz-transition-property: left;
+  -webkit-transition-property: left;
+  left: -200px;
 }
+html[dir='rtl'] #sidebarContainer {
+  -moz-transition-property: right;
+  -webkit-transition-property: right;
+  right: -200px;
+}
+
+#outerContainer.sidebarMoving > #sidebarContainer,
 #outerContainer.sidebarOpen > #sidebarContainer {
   visibility: visible;
+}
+html[dir='ltr'] #outerContainer.sidebarOpen > #sidebarContainer {
   left: 0px;
 }
+html[dir='rtl'] #outerContainer.sidebarOpen > #sidebarContainer {
+  right: 0px;
+}
 
 #mainContainer {
   position: absolute;
@@ -66,20 +87,24 @@ body {
   right: 0;
   bottom: 0;
   left: 0;
-  -moz-transition-property: left;
   -moz-transition-duration: 200ms;
   -moz-transition-timing-function: ease;
-  -webkit-transition-property: left;
   -webkit-transition-duration: 200ms;
   -webkit-transition-timing-function: ease;
 }
-#outerContainer.sidebarOpen > #mainContainer {
+html[dir='ltr'] #outerContainer.sidebarOpen > #mainContainer {
+  -moz-transition-property: left;
+  -webkit-transition-property: left;
   left: 200px;
 }
+html[dir='rtl'] #outerContainer.sidebarOpen > #mainContainer {
+  -moz-transition-property: right;
+  -webkit-transition-property: right;
+  right: 200px;
+}
 
 #sidebarContent {
   top: 32px;
-  left: 0;
   bottom: 0;
   overflow: auto;
   position: absolute;
@@ -88,6 +113,12 @@ body {
   background-color: hsla(0,0%,0%,.1);
   box-shadow: inset -1px 0 0 hsla(0,0%,0%,.25);
 }
+html[dir='ltr'] #sidebarContent {
+  left: 0;
+}
+html[dir='rtl'] #sidebarContent {
+  right: 0;
+}
 
 #viewerContainer {
   overflow: auto;
@@ -129,7 +160,6 @@ body {
 
 #toolbarViewer {
   position: relative;
-  margin-left: -1px;
   height: 32px;
   background-image: url(images/texture.png),
                     -moz-linear-gradient(hsla(0,0%,32%,.99), hsla(0,0%,27%,.95));
@@ -142,31 +172,53 @@ body {
               0 1px 0 hsla(0,0%,0%,.15),
               0 1px 1px hsla(0,0%,0%,.1);
 }
+html[dir='ltr'] #toolbarViewerLeft {
+  margin-left: -1px;
+}
+html[dir='rtl'] #toolbarViewerRight {
+  margin-left: -1px;
+}
 
-#toolbarViewerLeft {
+
+html[dir='ltr'] #toolbarViewerLeft,
+html[dir='rtl'] #toolbarViewerRight {
   position: absolute;
   top: 0;
   left: 0;
 }
-#toolbarViewerRight {
+html[dir='ltr'] #toolbarViewerRight,
+html[dir='rtl'] #toolbarViewerLeft {
   position: absolute;
   top: 0;
   right: 0;
 }
-#toolbarViewerLeft > *,
-#toolbarViewerMiddle > *,
-#toolbarViewerRight > * {
+html[dir='ltr'] #toolbarViewerLeft > *,
+html[dir='ltr'] #toolbarViewerMiddle > *,
+html[dir='ltr'] #toolbarViewerRight > * {
   float: left;
 }
+html[dir='rtl'] #toolbarViewerLeft > *,
+html[dir='rtl'] #toolbarViewerMiddle > *,
+html[dir='rtl'] #toolbarViewerRight > * {
+  float: right;
+}
 
-.splitToolbarButton {
+html[dir='ltr'] .splitToolbarButton {
   margin: 3px 2px 4px 0;
   display: inline-block;
 }
-.splitToolbarButton > .toolbarButton {
+html[dir='rtl'] .splitToolbarButton {
+  margin: 3px 0 4px 2px;
+  display: inline-block;
+}
+html[dir='ltr'] .splitToolbarButton > .toolbarButton {
   border-radius: 0;
   float: left;
 }
+html[dir='rtl'] .splitToolbarButton > .toolbarButton {
+  border-radius: 0;
+  float: right;
+}
 
 .toolbarButton {
   border: 0 none;
@@ -214,7 +266,8 @@ body {
               0 0 1px hsla(0,0%,0%,.05);
   z-index: 199;
 }
-.splitToolbarButton > .toolbarButton:first-child  {
+html[dir='ltr'] .splitToolbarButton > .toolbarButton:first-child,
+html[dir='rtl'] .splitToolbarButton > .toolbarButton:last-child {
   position: relative;
   margin: 0;
   margin-right: -1px;
@@ -222,7 +275,8 @@ body {
   border-bottom-left-radius: 2px;
   border-right-color: transparent;
 }
-.splitToolbarButton > .toolbarButton:last-child  {
+html[dir='ltr'] .splitToolbarButton > .toolbarButton:last-child,
+html[dir='rtl'] .splitToolbarButton > .toolbarButton:first-child {
   position: relative;
   margin: 0;
   margin-left: -1px;
@@ -238,8 +292,13 @@ body {
   box-shadow: 0 0 0 1px hsla(0,0%,100%,.08);
   display: inline-block;
   margin: 5px 0;
+}
+html[dir='ltr'] .splitToolbarButtonSeparator {
   float:left;
 }
+html[dir='rtl'] .splitToolbarButtonSeparator {
+  float:right;
+}
 .splitToolbarButton:hover > .splitToolbarButtonSeparator,
 .splitToolbarButton.toggled > .splitToolbarButtonSeparator {
   padding: 12px 0;
@@ -257,7 +316,6 @@ body {
 .dropdownToolbarButton {
   min-width: 16px;
   padding: 2px 6px 0;
-  margin: 3px 2px 4px 0;
   border: 1px solid transparent;
   border-radius: 2px;
   color: hsl(0,0%,95%);
@@ -274,6 +332,15 @@ body {
   -webkit-transition-timing-function: ease;
 }
 
+html[dir='ltr'] .toolbarButton,
+html[dir='ltr'] .dropdownToolbarButton {
+  margin: 3px 2px 4px 0;
+}
+html[dir='rtl'] .toolbarButton,
+html[dir='rtl'] .dropdownToolbarButton {
+  margin: 3px 0 4px 2px;
+}
+
 .toolbarButton:hover,
 .toolbarButton:focus,
 .dropdownToolbarButton {
@@ -336,7 +403,13 @@ body {
   max-width: 120px;
   padding: 3px 2px 2px;
   overflow: hidden;
-  background: url(images/toolbarButton-menuArrows.png) no-repeat 95%;
+  background: url(images/toolbarButton-menuArrows.png) no-repeat;
+}
+html[dir='ltr'] .dropdownToolbarButton {
+  background-position: 95%;
+}
+html[dir='rtl'] .dropdownToolbarButton {
+  background-position: 5%;
 }
 
 .dropdownToolbarButton > select {
@@ -359,12 +432,16 @@ body {
   border-bottom: 1px rgba(255, 255, 255, .5) solid;
 }
 
-.splitToolbarButton:first-child,
-.toolbarButton:first-child {
+html[dir='ltr'] .splitToolbarButton:first-child,
+html[dir='ltr'] .toolbarButton:first-child,
+html[dir='rtl'] .splitToolbarButton:last-child,
+html[dir='rtl'] .toolbarButton:last-child {
   margin-left: 4px;
 }
-.splitToolbarButton:last-child,
-.toolbarButton:last-child {
+html[dir='ltr'] .splitToolbarButton:last-child,
+html[dir='ltr'] .toolbarButton:last-child,
+html[dir='rtl'] .splitToolbarButton:first-child,
+html[dir='rtl'] .toolbarButton:first-child {
   margin-right: 4px;
 }
 
@@ -385,16 +462,26 @@ body {
   content: url(images/toolbarButton-sidebarToggle.png);
 }
     
-.toolbarButton.pageUp::before {
+html[dir='ltr'] .toolbarButton.pageUp::before {
   display: inline-block;
   content: url(images/toolbarButton-pageUp.png);
 }
+
+html[dir='rtl'] .toolbarButton.pageUp::before {
+  display: inline-block;
+  content: url(images/toolbarButton-pageUp-rtl.png);
+}
     
-.toolbarButton.pageDown::before {
+html[dir='ltr'] .toolbarButton.pageDown::before {
   display: inline-block;
   content: url(images/toolbarButton-pageDown.png);
 }
 
+html[dir='rtl'] .toolbarButton.pageDown::before {
+  display: inline-block;
+  content: url(images/toolbarButton-pageDown-rtl.png);
+}
+
 .toolbarButton.zoomOut::before {
   display: inline-block;
   content: url(images/toolbarButton-zoomOut.png);
@@ -625,6 +712,7 @@ canvas {
 }
 
 .page {
+  direction: ltr;
   width: 816px;
   height: 1056px;
   margin: 10px auto;
diff --git a/web/viewer.html b/web/viewer.html
index b4e4e1c77..0ec05e031 100644
--- a/web/viewer.html
+++ b/web/viewer.html
@@ -1,12 +1,15 @@
 <!DOCTYPE html>
-<html>
+<html dir="ltr">
   <head>
+    <meta charset="utf-8">
     <title>PDF.js viewer</title>
     <!-- PDFJSSCRIPT_INCLUDE_FIREFOX_EXTENSION -->
 
     <link rel="stylesheet" href="viewer.css"/>
+    <link rel="resource" type="application/l10n" href="locale.properties"/><!-- PDFJSSCRIPT_REMOVE_CORE -->
 
     <script type="text/javascript" src="compatibility.js"></script> <!-- PDFJSSCRIPT_REMOVE_FIREFOX_EXTENSION -->
+    <script type="text/javascript" src="../external/webL10n/l10n.js"></script><!-- PDFJSSCRIPT_REMOVE_CORE -->
 
     <!-- PDFJSSCRIPT_INCLUDE_BUILD -->
     <script type="text/javascript" src="../src/core.js"></script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
@@ -43,11 +46,11 @@
       <div id="sidebarContainer">
         <div id="toolbarSidebar">
           <div class="splitToolbarButton toggled">
-            <button id="viewThumbnail" class="toolbarButton toggled" title="Show Thumbnails" onclick="PDFView.switchSidebarView('thumbs')" tabindex="1">
-               <span>Thumbnails</span>
+            <button id="viewThumbnail" class="toolbarButton toggled" title="Show Thumbnails" onclick="PDFView.switchSidebarView('thumbs')" tabindex="1" data-l10n-id="thumbs">
+               <span data-l10n-id="thumbs_label">Thumbnails</span>
             </button>
-            <button id="viewOutline" class="toolbarButton" title="Show Document Outline" onclick="PDFView.switchSidebarView('outline')" tabindex="2">
-               <span>Document Outline</span>
+            <button id="viewOutline" class="toolbarButton" title="Show Document Outline" onclick="PDFView.switchSidebarView('outline')" tabindex="2" data-l10n-id="outline">
+               <span data-l10n-id="outline_label">Document Outline</span>
             </button>
           </div>
         </div>
@@ -65,20 +68,20 @@
 
             <div id="toolbarViewer">
               <div id="toolbarViewerLeft">
-                <button id="sidebarToggle" class="toolbarButton" title="Toggle Sidebar" tabindex="3">
-                  <span>Toggle Sidebar</span>
+                <button id="sidebarToggle" class="toolbarButton" title="Toggle Sidebar" tabindex="3" data-l10n-id="toggle_slider">
+                  <span data-l10n-id="toggle_slider_label">Toggle Sidebar</span>
                 </button>
                 <div class="toolbarButtonSpacer"></div>
                 <div class="splitToolbarButton">
-                  <button class="toolbarButton pageUp" title="Previous Page" onclick="PDFView.page--" id="previous" tabindex="4">
-                    <span>Previous</span>
+                  <button class="toolbarButton pageUp" title="Previous Page" onclick="PDFView.page--" id="previous" tabindex="4" data-l10n-id="previous">
+                    <span data-l10n-id="previous_label">Previous</span>
                   </button>
                   <div class="splitToolbarButtonSeparator"></div>
-                  <button class="toolbarButton pageDown" title="Next Page" onclick="PDFView.page++" id="next" tabindex="5">
-                    <span>Next</span>
+                  <button class="toolbarButton pageDown" title="Next Page" onclick="PDFView.page++" id="next" tabindex="5" data-l10n-id="next">
+                    <span data-l10n-id="next_label">Next</span>
                   </button>
                 </div>
-                <label class="toolbarLabel" for="pageNumber">Page: </label>
+                <label class="toolbarLabel" for="pageNumber" data-l10n-id="page_label">Page: </label>
                 <input type="number" id="pageNumber" class="toolbarField pageNumber" onchange="PDFView.page = this.value;" value="1" size="4" min="1" tabindex="6">
                 </input>
                 <span id="numPages" class="toolbarLabel"></span>
@@ -88,40 +91,40 @@
 
                 <!--
                 <input id="fileInput" class="fileInput" type="file" oncontextmenu="return false;" style="visibility: hidden; position: fixed; right: 0; top: 0" />
-                <button id="openFile" class="toolbarButton print" title="Open" tabindex="10" onclick="document.getElementById('fileInput').click()">
-                   <span>Open</span>
+                <button id="openFile" class="toolbarButton print" title="Open File" tabindex="10" data-l10n-id="open_file" onclick="document.getElementById('fileInput').click()">
+                   <span data-l10n-id="open_file_label">Open</span>
                 </button>
                 -->
 
                 <!--
-                <button id="print" class="toolbarButton print" title="Print" tabindex="11" onclick="window.print()">
-                  <span>Print</span>
+                <button id="print" class="toolbarButton print" title="Print" tabindex="11" data-l10n-id="print" onclick="window.print()">
+                  <span data-l10n-id="print_label">Print</span>
                 </button>
                 -->
 
-                <button id="download" class="toolbarButton download" title="Download" onclick="PDFView.download();" tabindex="12">
-                  <span>Download</span>
+                <button id="download" class="toolbarButton download" title="Download" onclick="PDFView.download();" tabindex="12" data-l10n-id="download">
+                  <span data-l10n-id="download_label">Download</span>
                 </button>
                 <!-- <div class="toolbarButtonSpacer"></div> -->
-                <a href="#" id="viewBookmark" class="toolbarButton bookmark" title="Bookmark (or copy) current location" tabindex="13"><span>Bookmark</span></a>
+                <a href="#" id="viewBookmark" class="toolbarButton bookmark" title="Current view (copy or open in new window)" tabindex="13" data-l10n-id="bookmark"><span data-l10n-id="bookmark_label">Current View</span></a>
               </div>
               <div class="outerCenter">
                 <div class="innerCenter" id="toolbarViewerMiddle">
                   <div class="splitToolbarButton">
-                    <button class="toolbarButton zoomOut" title="Zoom Out" onclick="PDFView.zoomOut();" tabindex="7">
-                      <span>Zoom Out</span>
+                    <button class="toolbarButton zoomOut" title="Zoom Out" onclick="PDFView.zoomOut();" tabindex="7" data-l10n-id="zoom_out">
+                      <span data-l10n-id="zoom_out_label">Zoom Out</span>
                     </button>
                     <div class="splitToolbarButtonSeparator"></div>
-                    <button class="toolbarButton zoomIn" title="Zoom In" onclick="PDFView.zoomIn();" tabindex="8">
-                      <span>Zoom In</span>
+                    <button class="toolbarButton zoomIn" title="Zoom In" onclick="PDFView.zoomIn();" tabindex="8" data-l10n-id="zoom_in">
+                      <span data-l10n-id="zoom_in_label">Zoom In</span>
                      </button>
                   </div>
                   <span class="dropdownToolbarButton">
-                     <select id="scaleSelect" onchange="PDFView.parseScale(this.value);" title="Zoom" oncontextmenu="return false;" tabindex="9">
-                      <option id="pageAutoOption" value="auto" selected="selected">Automatic Zoom</option>
-                      <option value="page-actual">Actual Size</option>
-                      <option id="pageFitOption" value="page-fit">Fit Page</option>
-                      <option id="pageWidthOption" value="page-width">Full Width</option>
+                     <select id="scaleSelect" onchange="PDFView.parseScale(this.value);" title="Zoom" oncontextmenu="return false;" tabindex="9" data-l10n-id="zoom">
+                      <option id="pageAutoOption" value="auto" selected="selected" data-l10n-id="page_scale_auto">Automatic Zoom</option>
+                      <option id="pageActualOption" value="page-actual" data-l10n-id="page_scale_actual">Actual Size</option>
+                      <option id="pageFitOption" value="page-fit" data-l10n-id="page_scale_fit">Fit Page</option>
+                      <option id="pageWidthOption" value="page-width" data-l10n-id="page_scale_width">Full Width</option>
                       <option id="customScaleOption" value="custom"></option>
                       <option value="0.5">50%</option>
                       <option value="0.75">75%</option>
@@ -142,22 +145,22 @@
         </div>
 
         <div id="loadingBox">
-            <div id="loading">Loading... 0%</div>
+            <div id="loading" data-l10n-id="loading" data-l10n-args='{"percent": 0}'>Loading... 0%</div>
             <div id="loadingBar"><div class="progress"></div></div>
         </div>
 
         <div id="errorWrapper" hidden='true'>
           <div id="errorMessageLeft">
             <span id="errorMessage"></span>
-            <button id="errorShowMore" onclick="" oncontextmenu="return false;">
+            <button id="errorShowMore" onclick="" oncontextmenu="return false;" data-l10n-id="error_more_info">
               More Information
             </button>
-            <button id="errorShowLess" onclick="" oncontextmenu="return false;" hidden='true'>
+            <button id="errorShowLess" onclick="" oncontextmenu="return false;" data-l10n-id="error_less_info" hidden='true'>
               Less Information
             </button>
           </div>
           <div id="errorMessageRight">
-            <button id="errorClose" oncontextmenu="return false;">
+            <button id="errorClose" oncontextmenu="return false;" data-l10n-id="error_close">
               Close
             </button>
           </div>
diff --git a/web/viewer.js b/web/viewer.js
index 26c5de805..e8eb9ad3b 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -15,6 +15,8 @@ var kMaxScale = 4.0;
 var kImageDirectory = './images/';
 var kSettingsMemory = 20;
 
+var mozL10n = document.mozL10n || document.webL10n;
+
 function getFileName(url) {
   var anchor = url.indexOf('#');
   var query = url.indexOf('?');
@@ -347,11 +349,13 @@ var PDFView = {
       },
       function getDocumentError(message, exception) {
         var loadingIndicator = document.getElementById('loading');
-        loadingIndicator.textContent = 'Error';
+        loadingIndicator.textContent = mozL10n.get('loading_error_indicator',
+          null, 'Error');
         var moreInfo = {
           message: message
         };
-        self.error('An error occurred while loading the PDF.', moreInfo);
+        self.error(mozL10n.get('loading_error', null,
+          'An error occurred while loading the PDF.'), moreInfo);
         self.loading = false;
       },
       function getDocumentProgress(progressData) {
@@ -458,17 +462,29 @@ var PDFView = {
     };
     moreInfoButton.removeAttribute('hidden');
     lessInfoButton.setAttribute('hidden', 'true');
-    errorMoreInfo.value = 'PDF.JS Build: ' + PDFJS.build + '\n';
+    errorMoreInfo.value =
+      mozL10n.get('error_build', {build: PDFJS.build},
+      'PDF.JS Build: {{build}}') + '\n';
 
     if (moreInfo) {
-      errorMoreInfo.value += 'Message: ' + moreInfo.message;
+      errorMoreInfo.value +=
+        mozL10n.get('error_message', {message: moreInfo.message},
+        'Message: {{message}}');
       if (moreInfo.stack) {
-        errorMoreInfo.value += '\n' + 'Stack: ' + moreInfo.stack;
+        errorMoreInfo.value += '\n' +
+          mozL10n.get('error_stack', {stack: moreInfo.stack},
+          'Stack: {{stack}}');
       } else {
-        if (moreInfo.filename)
-          errorMoreInfo.value += '\n' + 'File: ' + moreInfo.filename;
-        if (moreInfo.lineNumber)
-          errorMoreInfo.value += '\n' + 'Line: ' + moreInfo.lineNumber;
+        if (moreInfo.filename) {
+          errorMoreInfo.value += '\n' +
+            mozL10n.get('error_file', {file: moreInfo.filename},
+            'File: {{file}}');
+        }
+        if (moreInfo.lineNumber) {
+          errorMoreInfo.value += '\n' +
+            mozL10n.get('error_line', {line: moreInfo.lineNumber},
+            'Line: {{line}}');
+        }
       }
     }
     errorMoreInfo.rows = errorMoreInfo.value.split('\n').length - 1;
@@ -477,7 +493,8 @@ var PDFView = {
   progress: function pdfViewProgress(level) {
     var percent = Math.round(level * 100);
     var loadingIndicator = document.getElementById('loading');
-    loadingIndicator.textContent = 'Loading... ' + percent + '%';
+    loadingIndicator.textContent = mozL10n.get('loading', {percent: percent},
+      'Loading... {{percent}}%');
 
     PDFView.loadingBar.percent = percent;
   },
@@ -513,7 +530,8 @@ var PDFView = {
     var pagesCount = pdfDocument.numPages;
     var id = pdfDocument.fingerprint;
     var storedHash = null;
-    document.getElementById('numPages').textContent = 'of ' + pagesCount;
+    document.getElementById('numPages').textContent =
+      mozL10n.get('page_of', {pageCount: pagesCount}, 'of {{pageCount}}');
     document.getElementById('pageNumber').max = pagesCount;
     PDFView.documentFingerprint = id;
     var store = PDFView.store = new Settings(id);
@@ -827,7 +845,8 @@ var PageView = function pageView(container, pdfPage, id, scale,
       var rect = viewport.convertToViewportRectangle(item.rect);
       rect = PDFJS.Util.normalizeRect(rect);
       image.src = kImageDirectory + 'annotation-' + type.toLowerCase() + '.svg';
-      image.alt = '[' + type + ' Annotation]';
+      image.alt = mozL10n.get('text_annotation_type', {type: type},
+        '[{{type}} Annotation]');
       var content = document.createElement('div');
       content.setAttribute('hidden', true);
       var title = document.createElement('h1');
@@ -1008,8 +1027,10 @@ var PageView = function pageView(container, pdfPage, id, scale,
         delete self.loadingIconDiv;
       }
 
-      if (error)
-        PDFView.error('An error occurred while rendering the page.', error);
+      if (error) {
+        PDFView.error(mozL10n.get('rendering_error', null,
+          'An error occurred while rendering the page.'), error);
+      }
 
       self.stats = pdfPage.stats;
       self.updateStats();
@@ -1153,7 +1174,8 @@ var DocumentOutlineView = function documentOutlineView(outline) {
   if (!outline) {
     var noOutline = document.createElement('div');
     noOutline.classList.add('noOutline');
-    noOutline.textContent = 'No Outline Available';
+    noOutline.textContent = mozL10n.get('no_outline', null,
+      'No Outline Available');
     outlineView.appendChild(noOutline);
     return;
   }
@@ -1337,6 +1359,12 @@ window.addEventListener('load', function webViewerLoad(evt) {
   if ('disableWorker' in hashParams)
     PDFJS.disableWorker = (hashParams['disableWorker'] === 'true');
 
+  var locale = !PDFJS.isFirefoxExtension ? navigator.language :
+    FirefoxCom.request('getLocale', null);
+  if ('locale' in hashParams)
+    locale = hashParams['locale'];
+  mozL10n.language.code = locale;
+
   if ('disableTextLayer' in hashParams)
     PDFJS.disableTextLayer = (hashParams['disableTextLayer'] === 'true');
 
@@ -1531,6 +1559,10 @@ function selectScaleOption(value) {
   return predefinedValueFound;
 }
 
+window.addEventListener('localized', function localized(evt) {
+  document.getElementsByTagName('html')[0].dir = mozL10n.language.direction;
+}, true);
+
 window.addEventListener('scalechange', function scalechange(evt) {
   var customScaleOption = document.getElementById('customScaleOption');
   customScaleOption.selected = false;