json convert to string

function stringfy (obj) {    var t = typeof (obj);    if (t != "object" || obj === null) {        // simple data type        if (t == "string") obj = '"'+obj+'"';        return String(obj);    }    else {        // recurse array or object        var n, v, json = [], arr = (obj && obj.constructor == Array);        for (n in obj) {            v = obj[n]; t = typeof(v);            if (t == "string") v = '"'+v+'"';            else if (t == "object" && v !== null) v = JSON.stringify(v);            json.push((arr ? "" : '"' + n + '":') + String(v));        }        return (arr ? "[" : "{") + String(json) + (arr ? "]" : "}");    }};