5 steps for i18n in Windows 8 Metro style apps (JS)

1. Create three folders in your project root:

   |
   --strings
     |
     --en-US
     |
     | 
     --de-DE (or another language and country code)

2. Then create in your in each of your two subfolders a Resource File (*.resjson):

   |
   --strings
     |
     --en-US
     | |
     | --resources.resjson
     |
     --de-DE (or another language and country code)
       |
       --resources.resjson
   

3. Enter your strings in JSON format.
4. i18n in your HTML:
   
   1. <element data-win-res="{textContent: '[resStringName]'}"></element>
   2. Call WinJS.Resources.processAll() in your JavaScript, after the DOM was loaded, e.g.:
      

      var app = WinJS.Application;
      // ...
      app.onloaded = function (args) {
        WinJS.Resources.processAll();
      }
      
      

5. i18n in your JavaScript:
   

   var str = WinJS.Resources.getString("[resStringName]").value;