理解javascript中的原型和原型链

function Student(name){
 this.name = name;
}
 
var Kimy = new Student("Kimy");
 
Student.prototype.say = function(){
 console.log(this.name + "say");
}

Kimy.say();
//Kimysay

// 构造方法
function Foo(y) {
 this.y = y;
}
 
Foo.prototype.x = 10;
 
// 继承方法"calculate"
Foo.prototype.calculate = function (z) {
 return this.x + this.y + z;
};
 
// 使用foo模式创建 "b" and "c"
var b = new Foo(20);
var c = new Foo(30);
 
// 调用继承的方法
b.calculate(30); // 60
c.calculate(40); // 80
 
 
console.log(
 
 b.__proto__ === Foo.prototype, // true
 c.__proto__ === Foo.prototype, // true
 
 b.constructor === Foo, // true
 c.constructor === Foo, // true
 Foo.prototype.constructor === Foo // true
 
 b.calculate === b.__proto__.calculate, // true
 b.__proto__.calculate === Foo.prototype.calculate // true
 
);

Object instanceof Function
//true
Function instanceof Object
//true

var Kimy = {}; 

Kimy.__proto__ = Student.prototype;

Student.call(Kimy);