Prototypal OOP

"use strict";

// Extend
if (!Object.create) {
    Object.create = function (obj) {
        function f() { };
        f.prototype = obj;
        return new f();
    }
}

if (!Object.prototype.extend) {
    Object.prototype.extend = function (properties) {
        function f() { };
        f.prototype = Object.create(this);
        for (var prop in properties) {
            f.prototype[prop] = properties[prop];
        }
        f.prototype._super = this;
        return new f();
    }
}

// Prototypal OOP
var Human = {
    init: function (fname, lname, age) {
        this.fname = fname;
        this.lname = lname;
        this.age = age;
    }
};

var Student = Human.extend({
    init: function (fname, lname, age, grade) {
        this._super.init(fname, lname, age);
        this.grade = grade;
    },
    introduce: function () {
        return "Hello! My name is " + this.fname + " " + this.lname + ", my age is: " + this.age + " grade: " + this.grade;
    }
});

var pesho = Object.create(Student);
pesho.init("Pesho", "Mastikata", 12, 2);
console.log(pesho.introduce());