A javascript implementation of the RFC 6901 Spec: http://tools.ietf.org/html/rfc6901
There are many fine implementations of the spec but JSONPointer offers additional functionality.
var doc={
"foo" : {
"bar" : "value"
}
};
var pointer=new JSONPointer("/foo/bar");
pointer.evaluate(doc); // returns "value"
JSONPointer can be extended to support various needs.
var pointer=new JSONPointer("foo.bar", {delimiter:"."});
pointer.evaluate(doc); // returns "value"
JSONPointer also offers a class factory for creating custom pointer types.
var DotPointer=JSONPointer.Factory({delimiter:"."});
var pointer=new DotPointer("foo.bar");
pointer.evaluate(doc); // returns "value"