Object Oriented Programming In Javascript

Yes, there is OOP in JavaScript.  The below code are notes that I took during my first week of Advanced Javascript class that I am currently enrolled in at Ryerson University.  These are working code.  I used the free Komodo editor from ActiveState.  It is a cool editor with colored syntax and intellisense and works with HTML and Javascript, and even Perl, PHP, Phyton and Ruby.

// creating native object types like dates, strings, numbers, and booleans
var date = new Date();
var str1 = "Sotto";
var str2 = new String("Rodan");
var num1 = 0.35;
var num2 = new Number(0.4);
var bool1 = true;
var bool2 = new Boolean(false);

// calling native object types' properties and methods
var strLen = str1.length;
var fixedNum = num1.toFixed(4);

// creating custom objects, in this example blank objects
var obj1 = new Object();
var obj2 = {};

// adding properties and methods after creating a custom object
obj1.prop1 = "Object1's Property1";
obj1["prop1"] = "Object1's Property1 using []";
obj1.func1 = function () {
return "Object1's Function1";
obj1["func1"] = function () {
return "Object1's Function1 using []";

// you can also add properties and methods to the native objects
// using the prototype object
Date.prototype.myCustomProperty = "My Custom Property";
var date = new Date();

// some like the Math object does not have the prototype object
// so you add directly
Math.myCustomProperty = "My Custom Property";

// removing property or function from an object
delete obj1.func1;
obj1.func1(); // displays undefined

// creating a custom object with properties and functions
// notice you use , to separate each properties and functions in {}
var invoice = {
taxRate: 0.35,
dueDays: 30,
getSalesTax: function(subTotal) {
return (subTotal * invoice.taxRate);
getTotal: function(subTotal, salesTax) {
return (subTotal + salesTax);

// creating object references
var today2 = new Date();
var now = today2;

// creating a class
// you create a constructor function first
var Vehicle = function(make, model) {
this.make = make;
this.model = model;
this.miles = 0;

// then create the class methods and other properties
// through the prototype object
Vehicle.prototype.drive = function(miles) {
this.miles += miles;
return this;

Vehicle.prototype.canFly = false;

var myCar = new Vehicle("Honda", "CRV");

// creating a sub class (inheritance)
var Car = function(make, model, door, suv) {
this.make = make;
this.model = model;
this.door = door;
// example of optional arguments
if (arguments.length == 4) {
this.suv = suv
else {
this.suv = false;
this.miles = 0;

Car.prototype = new Vehicle();

var my2ndCar = new Car("Honda", "Odyssey", 4, false);

// notice above the method is called one after the other
// this is possible if the method is a cascading method
// a cascading method is one that returns the this object

// looping through the object's properties and methods
for (var property in my2ndCar) {

// checking if the object's property is enumerable
alert(my2ndCar.propertyIsEnumerable("make")); // displays true
alert(my2ndCar.propertyIsEnumerable("drive")); // displays false

// using the in operator
alert("make" in my2ndCar); // displays true
alert("drive" in my2ndCar); // displays true

// using the instanceof operator
alert(my2ndCar instanceof Car); // displays true
alert(my2ndCar instanceof Vehicle); // displays true
alert(my2ndCar instanceof Object); // displays true
alert(my2ndCar instanceof String); // displays false

// using the typeof operator
alert(typeof my2ndCar); // displays object
alert(typeof Vehicle); // displays function
alert(typeof Car); // displays function
alert(typeof my2ndCar.make); // displays string
alert(typeof my2ndCar.drive); // displays function


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