js中创建对象的三种方法

第一种：原型法

let obj = new Object();
obj.id = 1;
obj.name = "路人甲";
obj.age = "22";
obj.hello = function(){
    document.write("测试方法")
}
obj.add = function(x,y){
    return x + y;
}
obj.hello();
document.write(obj.add(5,6));
document.write(obj.id);
document.write(obj.name);
document.write(obj.age);

第二种：常量法（最常见）

let user={
    id:3,
    name:"路人丙",
    age:23,
    hello:function(){
        document.write("测试方法！");
    },
    add:function(x,y){
        return x + y;
    },
    myminus:minus
}
    function minus(x,y){ return x-y}
document.write(user.id + "    " + user.name + "    " + user.age + "   ");
user.hello();
document.write(user.add(5,6));
document.write(user.myminus(10,20));

第三种：构造函数法

function user(id,name,age){
    this.id = id;
    this.name = name;
    this.age = age;
    this.hello = function(){
        document.write("ceshi");
    }
    this.Myminus = minus;
}
function minus(x,y){
    return x - y;
}
let u = new user(2,"路人丁",22);
document.write(u.id + u.name + u.age);
u.hello();
document.write(u.Myminus(20,30));