February 12, 2001 - Inheritance between Classes

Yehuda Shiran February 12, 2001
Inheritance between Objects
Tips: February 2001

Yehuda Shiran, Ph.D.
Doc JavaScript

Although JavaScript does not support an explicit inheritance operator, you can implement inheritance in JavaScript by having the subclass call the superclass. In the following example, we have two class definitions: superclass() and subclass(). The class subclass() first assigns its superclass() to the inheritFrom() method, and then calls the newly-defined method:

function superclass() {
  this.info = alert("Defining the Superclass");
}
function subclass() {
  this.inheritFrom = superclass;
  this.inheritFrom();
  this.info = alert("Overriding the Superclass");
}

To activate the generation of subclass(), click here. This button calls the following function:

function createSubclass() {
  var newClass = new subclass();
}

Notice the alert boxes. They show that the info method is first defined in superclass() and then is being overridden in subclass().