Recently Google released Caja. In doing so, they also revealed their own script for converting a JSON string to a JavaScript object. Choices are nice, so enjoy, courtesy of google! If you have no idea what I am talking about read on.
Due to certain security concerns, it's appropriate in most scenarios to convert a JSON string to an object without using just the eval method. If this is news to you, I suggest reading Douglas Crockford's article discussing this topic.