You need to pull this URL off the script element: `<script ... data-baseuri="...">`.  So this should be something like:

```javascript
var webxrayScript = document.querySelector(".webxray"), 
  baseURI = webxrayScript.dataset.baseuri,
  lang = webxrayScript.dataset.lang,
  url = baseURI + "/strings/" + lang;
...
Localized.ready(function(){...}, {url: url});
```

Also, we should fix the webmaker-i18n module's Localized.ready to accept the options first, before the callback.  I can do that.