var person = new Object();
//純值
person["firstname"] = "Tony";
//兩種方式取值
console.log(person[firstNameProperty])
var firstNameProperty = "firstname";
console.log(person.firstname)
//物件 (sub object)
person.address = new Object();
person.address.street = "111 main st.";
person.address.city = "new york";