I'm studying the concept of inheritance in Javascript, and the tutorial I'm looking at uses this code:

// define the Student class
function Student() {
  // Call the parent constructor
  Person.call(this);
}

// inherit Person
Student.prototype = new Person();

// correct the constructor pointer because it points to Person
Student.prototype.constructor = Student;

My question is, why is it necessary to both call the parent constructor, Person.call(this), and set the Student prototype equal to a new Person object (i.e. Student.prototype = new Person();)?