JS初步继承机制.

JS继承分为:类式继承和原型式继承.

类式继承源于大多程序员熟知的传统形式.所以比较容易接受. 原型式继承是源于JS独特的原型机制.因此效率更高.至于哪一种还是看个人习惯了.

这里只是构造了个简单的类式继承的原型.

function inherit(subclass, superclass) {
    // 建立空的构造器.避免了superclass的实例化.
    var F = function() {};
    F.prototype = superclass.prototype;
    subclass.prototype = new F();
    // 重置原型链
    subclass.prototype.constructor = subclass;
    // 松耦合实例继承.并保证superclass的构造器指向正确
    subclass.superclass = superclass.prototype;
    if(superclass.prototype.constructor == Object.prototype.constructor) {
        superclass.prototype.constructor = superclass;
    }
}
/* superclass */
function Person( name ) {
    this.name = name;
};
Person.prototype.getName = function() {
    return this.name;
};

/* subclass */
function Author( name, books ) {
    // 这样就可以和Person耦合松散.
    Author.superclass.constructor.call(this, name);
    this.books = books;
};
inherit(Author, Person);
Author.prototype.getBooks = function() {
    return this.books;
}

var a = new Author('kc', 'dd');
alert(a.getName())
</script>

上面的例子就是Author继承了Person类