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.
BROWSER STATS [% share]
(2013/10/31) IE7:0.5, IE8:8.6, IE9:5.3, IE10:12.3, FF:17.7, CH:41.8, SF:8.1, MOBILE:20.4