如何在javascripts/jquery中操作json对象？

var jsonObj = {
  "name": "John",
  "age": 30,
  "city": "New York"
};

var jsonString = JSON.stringify(jsonObj);

var parsedJsonObj = JSON.parse(jsonString);

for (var key in jsonObj) {
  console.log(key + ": " + jsonObj[key]);
}

jsonObj["country"] = "USA";

delete jsonObj.age;

jsonObj.city = "Los Angeles";

$.each(jsonObj, function(key, value) {
  console.log(key + ": " + value);
});

if (jsonObj.hasOwnProperty("name")) {
  console.log("Name exists");
} else {
  console.log("Name does not exist");
}

var jsonObj2 = {
  "country": "USA",
  "state": "California"
};

var mergedJsonObj = $.extend({}, jsonObj, jsonObj2);