I assume you're talking about XML DTDs, which are completely different from what I'm suggesting. DTDs are part of the XML spec and are written in XML, making them extremely unwieldy. My suggestion for JSON validation is that it should be part of the local JSON API and that it should be written in the language you're using to call the JSON API.
I'm also going to have to stick a stonking big [[citation needed]] on your claim that JSON became successful because it doesn't do this. It's about as believable as the common headlines of the form "Stock X Rises/Falls on Event" which are nonsensical post-hoc constructions and poster boys for "correlation does not imply causation".
I'm also going to have to stick a stonking big [[citation needed]] on your claim that JSON became successful because it doesn't do this. It's about as believable as the common headlines of the form "Stock X Rises/Falls on Event" which are nonsensical post-hoc constructions and poster boys for "correlation does not imply causation".