简单的方式

function Person() {this.name = 'person';
}
Person.prototype.say = function() {};function Child() {this.name = 'child';
}
Child.prototype = new Person();var child = new Child();

缺点：其实child并不需要person里面的name属性

借用构造函数

function Person() {this.name = 'person';
}
Person.prototype.say = function() {};function Child() {Person.call(this, arguments)
}var child = new Child();

缺点：仅会复制父类对象的属性作为子类自身的属性, 仅仅是复制**

优点：可以获得父对象自身的真实副本，子类和父类没有关系，不会影响到父类**

借用构造函数是实现多继承

function CatWings() {Cat.call(this, arguments)Brid.call(this, arguments)
}

借用构造函数和实现原型

function Person() {this.name = 'person';
}
Person.prototype.say = function() {};function Child() {Person.call(this, arguments)// this.name = 'child'
}Child.prototype = new Person()var child = new Child();
delete child.name;
// 可以看到访问：child.name的是prototype的

name属性被继承了2次

缺点：所有从Person继承的类，都是可以更改到Person的原型方法

临时构造函数

function inherit(Child, Parent) {var F = function(){}F.prototype = Parent.prototype;Child.prototype = new F();// Child.prototype.constructor = Child// Child.superclass = Parent.prototype;
}// 每次都要创建一个空的F
var inherit = (function(){var F = Function(){};return function() {F.prototype = Parent.prototype;Child.prototype = new F();// Child.prototype.constructor = Child// Child.superclass = Parent.prototype;}
})();

Klass

var Klass = function (Parent, props) {if(props == undefined && typeof Parent == 'object') {props = Parent;Parent = null;}Parent = Parent || {};props = props || {};var Child = function() {if(Child.superclass.hasOwnProperty('__construct')) {Child.superclass['__construct'].apply(this, arguments);}if(Child.prototype.hasOwnProperty('__construct')) {Child.prototype['__construct'].apply(this, arguments);}};var F = function() {};F.prototype = Parent.prototype;Child.prototype = new F();Child.prototype.constructor = Child;Child.superclass = Parent.prototype;for(var i in props) {if(props.hasOwnProperty(i)) {Child.prototype[i] = props[i];}}return Child;
}function Animal() {}Animal.prototype.__construct = function(name) {this.name = name
};Animal.prototype.getName = function() {return this.name;
};var Dog = Klass(Animal, {__construct: function(name, age) {this.age = age;},run: function() {console.log('My name is %s, I\'m %s years old ,  I\'m Running', this.getName(), this.age);}
});var dog = new Dog('xixi', 26)