I get the following error in IE 9 SCRIPT5009: \'JSON\' is undefined only when in compatability mode. the line causing this error is
SCRIPT5009: \'JSON\' is undefined
JSON.string
Just an update (2013!) to the links provided above-
Per http://www.json.org/js.html, a link at the bottom of the page will refer you to the latest implementation:
https://github.com/douglascrockford/JSON-js