直接定义：
var person = { 'name': 'John Doe', 'age': 20, 'work': ['programmer', 'deliver'] };
先定义对象，再赋值：
var p = new Map(); p['name'] = 'Jane Doe'; p['age'] = 22; p['work'] = ['programmer', 'deliver'];
person['name'] // 'John Doe'