json had no functions, it's just a data format.
just like xml needs a dom document interface, json needs a runtime.
if you want something a little higher-level, there a lot of libs out there.
you can get an xpath simulator, an sql simulator, and lots of tools like that; youre not locked into a particular proprietary interface like you are with xml.
(2013/5) HTML5:90.2% MOB:14% IE7:0.5% IE8:8.6% IE9:9.8% IE10:10%