Personally, I don't like the use of indexing to determine the JSON structure (like this `<input name="foo[0][1]">`). I think it's way more powerful to derive the JSON structure from the DOM tree. That's why I wrote some code to do exactly that: https://gist.github.com/mjepronk/5b33eaa90ecf11a5c2c47935a2c...
The use of `<fieldset>` and `<section>` may not be the best choice. You could use `data-` attributes on arbitrary tags for instance.
The use of `<fieldset>` and `<section>` may not be the best choice. You could use `data-` attributes on arbitrary tags for instance.