//your object
var o = {
    foo:"bar",
    arr:[1,2,3],
    subo: {
        foo2:"bar2"
    }
};

//called with every property and it's value
function process(key,value) {
    log(key + " : "+value);
}

function traverse(o,func) {
    for (i in o) {
        func.apply(this,[i,o[i]]);
        if (typeof(o[i])=="object") {
            //going on step down in the object tree!!
            traverse(o[i],func);
        }
    }
}

//that's all... no magic, no bloated framework
traverse(o,process);

$.each(myJsonObj, function(key,val){
    // do something with key and val
});

function traverse(jsonObj) {
    if( typeof jsonObj == "object" ) {
        $.each(jsonObj, function(k,v) {
            // k is either an array index or object key
            traverse(v);
        }
    }
    else {
        // jsonOb is a number or string
    }
}

function js_traverse(o) {
    var type = typeof o
    if (type == "object") {
        for (var key in o) {
            print("key: ", key)
            js_traverse(o[key])
        }
    } else {
        print(o)
    }
}

js> foobar = {foo: "bar", baz: "quux", zot: [1, 2, 3, {some: "hash"}]}
[object Object]
js> js_traverse(foobar)
key:  foo
bar
key:  baz
quux
key:  zot
key:  0
1
key:  1
2
key:  2
3
key:  3
key:  some
hash

function traverse(o,func) {
    for (i in o) {
        func.apply(this,[i,o[i]]);
        if (typeof(o[i])=="object") {
            //going on step down in the object tree!!
            traverse(o[i],func);
        }
    }
}