Inheritance Tutorial Object Oriented Class Programming

In all programming languages that sport object oriented features there is a concept known as "Inheritance". Inheritance is when an object inherits all of the properties and methods of its parent object, to become a specialized version of the parent object. In JavaScript we use the prototype property to establish subclasses that inherit the characteristics of our parent classes. This results in a specialized subclass that can retain its own properties and methods, as well as inherit all of the properties and methods of the parent class.

<script>
// Establish a parent class
function Parentclass(){
    this.parent_property1 = "Hola";
    this.parentmethod1 = function parentmethod1(arg1){
        return arg1+" Parent method 1 return data ...";
    }
}
// Establish a child class
function Childclass(){
    this.child_property1 = "Adios";
    this.childmethod1 = function childmethod1(arg1){
        return arg1+" Child method 1 return data ...";
    }
}
// Make the Childclass inherit all of the Parent class characteristics
// by using the prototype property, explained in depth here: youtube.com/watch?v=EBoUT2eBlT4
Childclass.prototype = new Parentclass();
// Create a new instance of Childclass
var instance1 = new Childclass();
// Check to see if instance1 is an instance of both objects
alert( instance1 instanceof Parentclass );
alert( instance1 instanceof Childclass );
// Access the instance methods and properties
alert( instance1.parentmethod1("RESULT: ") );
alert( instance1.childmethod1("RESULT: ") );
alert( instance1.parent_property1 );
alert( instance1.child_property1 );
// Override parentmethod1 in the Childclass
Childclass.prototype.parentmethod1 = function parentmethod1(arg1){
    return arg1+" I have overridden Parent method 1";
}
alert( instance1.parentmethod1("RESULT: ") );
</script>