gistfile1.txt

function Father(first_name) {
 this.first_name = name;
}

var John = new Father('John');

function Son() {
 Father.apply(this, arguments);
}

Son.prototype = John;

var Johnny = new Son('Johnny');

Johnny.last_name

John.last_name = 'Smith';

Johnny.last_name

function sum (a, b, c) {
 return a+b+c;
}