@rwaldron: Our [documentation](http://api.jquery.com/jQuery.parseJSON/) specifies that `jQuery.parseJSON` accepts string input, which is a strictly smaller domain than `JSON.parse`. Guaranteeing success on `null` input means reverting ae72581d62ba9a50aa1bf9ce799601d25cf05553 (admittedly not a big deal) and no longer always deferring to `JSON.parse` when available—both here *and* in [master](https://github.com/jquery/jquery/blob/ff365d305fc22f40f4df9c4a6c7b1ca6c3c9800d/src/ajax/parseJSON.js#L5)—which seems like a lot of trouble for undocumented input.