javascript【继承实现方式 】

一.call() 和 apply()用法

function Animail(){
this.name="动物";
this.showName = function(){
alert(this.name);
};
}
function Cat(){
this.name = "猫咪";
}
var animail = new Animail();
var cat = new Cat();
animail.showName.call(cat);

function myFunction(a,b,c){
this.a = a;
this.b = b;
this.c = c;

}
var obj = new Object();
alert(obj.a); // undefined
myFunction.apply(obj,[2,5,8]);
//myFunction.call(obj,2,5,8);
alert(obj.a);//2

二. prototype

function Animail(){}

Animail.prototype.name = "动物";
Animail.prototype.age = 2;
Animail.prototype.type = "001";
function Cat(){
this.name = "猫咪";
this.age = 3;
}

Cat.prototype = Animail.prototype;

var animail = new Animail();
var cat = new Cat();

alert(cat.name); // cat 自己的name:猫咪
alert(cat.age); //cat 自己的age:3
alert(cat.type); //Animail的type:2