Javascript inheritance and polymorphism

inheritance.js

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

Person.prototype = {
  sayHi: function() {
    console.log('Hi, my name is ' + this.name);
  },
  parentClassMethod: function() {
    console.log('Method from Person class called on ' + this.name);
  }
};

var Student = function(name, carreerPath) {
  Person.call(this, name); // call parent constructor
  this.carreerPath = carreerPath;
};
Student.prototype = Object.create(Person.prototype); //inherit parent prototype object
Student.prototype.constructor = Student; //overwrite constructor
Student.prototype.sayHi = function() { //override sayHi function
  console.log('Hi, I am ' + this.name + ' and I study ' + this.carreerPath);
};

var person = new Person('John');
person.sayHi();
person.parentClassMethod();

var student = new Student('Ramon', 'Engineering');
student.sayHi();
student.parentClassMethod();

if (student instanceof Person) {
  console.log('Student is instance of Person');
}
if (student instanceof Student) {
  console.log('Student is instance of Student');
}
if (person instanceof Person) {
  console.log('person is instance of Person');
}
if (person instanceof Student) {
  console.log('person is instance of Student');
}