Ask HN: Trusted JSON Parser, why doesnt browsers themselves provide one?

I write many Firefox plug-ins and other JavaScript code where I have to deal with lots of JSON data. The real strength of JSON data while using it with JS is that you dont have to bother much about parsing it, which is a real headache if you are using XML. But then most of the code reviewers including JSLint display "eval" as unsafe. I then end up using Jquery, prototype etc to parse it. I wanted to know if there is a better way. Why dont browesrs provide a safe alternative to eval? And parsing it by custom doesnt make it 100% safe either.