That's correct. Currently, Firefox is the only browser that implements the JSON routines exactly as described in the spec (parsing since version 5.0, and serial

That's correct. Currently, Firefox is the only browser that implements the JSON routines exactly as described in the spec (parsing since version 5.0, and serializing since 6.0)...others deviate in one or more ways. It's not so much of a concern if you're targeting multiple browsers, as Firefox will correctly throw a `SyntaxError` when given malformed input, but it can certainly become problematic if you're relying on non-standard extensions in only one or two browsers.