To improve JSON interoperability the IETF should not define a more restricted version of JSON than defined by Ecma-404. Parsers exist that can parse "42" today and parsers that cannot parse "42" today can be meaningfully upgraded to do so too. This would not break those parsers, unless they depend on parsing 42 as an error, which is a far more unlikely scenario than parsing it as 42 given precedence. (Worth pondering about: what to do about a leading BOM, which XMLHttpRequest and browsers allow, but neither IETF nor Ecma-404 allow.) -- http://annevankesteren.nl/