Incorrect calculation when using offsetTop/offsetLeft

``` html
<html>
  <body>
    <div></div>
  </body>
  <script>
  var div = document.getElementsByTagName('div')[0];
  window.alert(div.offsetTop);
  window.alert(div.offsetLeft);
  </script>
</html>
```

Expected: `8`, `8`

Actual: `0`, `0`
