js 创建对象

function createPerson(name, age, job) {
var o = new Object();
o.name = name;
o.age = age;
o.job = job;
o.sayName = function () {
alert(this.name);
};
return o;
}
var person1 = createPerson("Nicholas", 29, "Software Engineer");
var person2 = createPerson("Greg", 62, "Doctor");

function Person(name, age, job) {
this.name = name;
this.age = age;
this.job = job;
this.sayName = function () {
alert(this.name);
};
}
var person1 = new Person("Nicholas", 29, "Software Engineer");
var person2 = new Person("Greg", 62, "Doctor");
//与工厂模式的不同点
//1.没有显示创造对象
//2.直接将属性和方法赋值给this
//3.没有return语句
//4.使用new创造对象

//使用方式
//1.当做构造函数使用
var person = new Person("Nicholas", 29, "Software");
person.sayName();//Nicholas

//2.作为普通函数调用
Person("Yellow", 27, "Doctor");
window.sayName();//Doctor

//3. 在另一个对象的作用域中调用
var o = new Object();
Person.call(o, "King", 25, "Nurse");
o.sayName();//King

//缺点:每个方法都要在每个实例上重新创建一遍

function Person() {
}
Person.prototype.name = "Yellowshorts";
Person.prototype.age = 29;
Person.prototype.job = "Software";
Person.prototype.sayName = function () {
alert(this.name);
}
var person1 = new Person();
person1.sayName();//Yellowshorts

var person2 = new Person();
person2.sayName();//Yellowshorts

alert(person1.sayName == person2.sayName);//true