You could try Xidel[1]. It supports JSON, XML and HTML using XPath/XQuery 3.1
It has some extensions to the standard that are pretty nice (JSONiq, CSS selectors, html “template” matching), but you can limit it to just standard XPath/XQuery if you like.
I recommend getting the nightly v .99 build if you give it a try, the stable .98 version is pretty old and I’ve had no issues with .99