function inherit(Target,Origin){
function F(){};
F.prototype = Origin.prototype; //
Targrt.prototype = new F();
Target.prototype.constructor = Target; //增加自己的constructor
Target.prototype._super = Origin; //找到自己的超类
}
function F(){}; 中间函数
F.prototype = Origin.prototype;
Targrt.prototype = new F();
或者
function proto(target,obj){
function Fn(){};
Fn.prototype = obj.prototype;
target.prototype = new Fn();
}
function proto2(target,obj){
function Fn(){};
Fn.prototype = obj.__proto__;
target.__proto__ = new Fn();
}
function son(){
this.name = 'tom';
};
function father(){
this.name = 'jim';
};
father.prototype = {
lastName:'Green'
}
//proto(son,father);
var s1 = new son();
var f1 = new father();
proto2(s1,f1);
console.log(s1.lastName);
类似的方法:原型继承
function Obj(o){
function f(){};
f.prototype = o;
return new f();
} function person(name,age){
this.name = name;
this.age = age;
} person.prototype.say = function(){
console.log(this.name+' : '+this.age);
}
var p1 = Obj(new person('zhangsan',23));
var p2 = Obj(new person('zhangsan',23));
console.log(p1);
console.log(p2);
console.log(p1.__proto__ === p2.__proto__);//false
console.log(p1.__proto__.__proto__ === p2.__proto__.__proto__);//true
p1.name1 = 'zhangsan';
p2.name1 = 'lisi';
p1.__proto__.name = 'liuliu';
console.log(p1);
console.log(p2);
//so要把原型的constructor回归到原型
p1.__proto__.constructor = person;
p1.__proto__._superProto = person.prototype;
console.log(p1.__proto__.constructor);
console.log(p1.__proto__._superProto);
闭包形式
var inherit = (function(){
var F = function(){}
return function(Target,Origin){
F.prototype = Origin.prototype;
Target.prototype = new F();
Target.prototype.constructor = Target;
Target.prototype._super = Origin;
console.log(1);
}
}())
function Father(){};
Father.prototype.name = 'zhang';
function Son(){};
inherit(Son,Father);
var father = new Father();
var son = new Son();
console.log(son.name);
问题:
var father = new Father();
var son = new Son();//son指向一个Son()对象 ,(son.__proto__ === Son.prototype)Son.prototype指向一个空间,
inherit(Son,Father);//Son.prototype指向了另一个空间,但是son.__proto__指向的空间并没有变化,所以name属性找不到
console.log(son.name);//undefined 实例:
function Father(){};
Father.prototype.lastName = 'Zhangsan';
var F = new Father();
function Son(){};
Father.prototype = new Son();
var P = new Father();
console.log(F.lastName);//zhangsan
console.log(P.lastName);//undefined