javascript 类式继承

function extend(subClass,superClass){

var F = function(){};
F.prototype = superClass.prototype;
subClass.prototype = new F();
subClass.prototype.constructor = subClass;

subClass.superclass = superClass.prototype;
if(superClass.prototype.constructor == Object.prototype.constructor){
superClass.prototype.constructor  = superClass;
}

}

function Person(name){
this.name=name;

}

Person.prototype.getName = function(){
return this.name;

}

function Author(name,books){
Author.superclass.constructor.call(this,name);
this.books = books;

}

extend(Author,Person);

Author.prototype.getBooks = function(){
return this.books
}

Author.prototype.getName = function(){ //子类通过superclass属性调用父类的方法，然后定制自己的内容
var name = Author.superclass.getName.call(this);
return name +"is a good name";

}