This is an open-source JavaScript widget for editing JSON data structures.  Features include a JSON structural view with buttons
for adding and removing objects and arrays, and a text view, with easy toggling between them, plus undo and redo, as well as a
resticted-editing mode.

The restricted editing mode is designed to make it easier to guide users in making changes that don't change the structure
of the original JSON. Of course, the text view makes it trivial to change the structure, so restricted editing is not a complete
solution. It must be paired, for example, with a comparison against a JSON Schema document to truly determine if the structure
has changed in an acceptable way.

Feel free to send patches!