构造函数绑定
function Animal() {
this.species = '动物';
}
function Cat(name,color){
Animal.apply(this, arguments);
this.name = name;
this.color = color;
}
var cat1 = new Cat("大毛","黄色");
console.log((cat1.species)); // 动物prototype模式
function Animal() {
this.species = '动物';
}
function Cat(name,color){
this.name = name;
this.color = color;
}
Cat.prototype = new Animal();
Cat.prototype.constructor = Cat;
var cat1 = new Cat("大毛","黄色");
console.log((cat1.species)); // 动物直接继承prototype
function Animal() {}
Animal.prototype.species = '动物';
function Cat(name,color){
this.name = name;
this.color = color;
}
Cat.prototype = Animal.prototype;
Cat.prototype.constructor = Cat;
var cat1 = new Cat("大毛","黄色");
console.log((cat1.species)); // 动物与前一种方法相比，这样做的优点是效率比较高（不用执行和建立Animal的实例了），比较省内存。缺点是 Cat.prototype和Animal.prototype现在指向了同一个对象，那么任何对Cat.prototype的修改，都会反映到Animal.prototype。
利用空对象作为中介 寄生组合继承
function Animal() {}
Animal.prototype.species = '动物';
function Cat(name,color){
Animal.call(this) // 借用构造函数继承属性
this.name = name;
this.color = color;
}
var F = function () {};
F.prototype = Animal.prototype;
Cat.prototype = new F();
Cat.prototype.constructor = Cat;
alert(Animal.prototype.constructor); // Animal
var cat1 = new Cat("大毛","黄色");
console.log((cat1.species)); // 动物
function Extend(child, parent) { // 继承原型的副本
//var F = function () {};
//F.prototype = parent.prototype;
//child.prototype = new F();
child.prototype = Object.create(parent.prototype)
child.prototype.constructor = child;
child.uber= parent.prototype;
}
Extend(Cat, Animal);
var cat1 = new Cat("大毛","黄色");
console.log((cat1.species)); // 动物
