访问json对象中的元素

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

var name = json.name; // 获取name的值，结果为"John"
var age = json.age; // 获取age的值，结果为30
var city = json.city; // 获取city的值，结果为"New York"

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

var key = "name";
var value = json[key]; // 获取name的值，结果为"John"

var specialKey = "city";
var specialValue = json[specialKey]; // 获取city的值，结果为"New York"