Objects in JavaScript

In real life we have a lot of objects all around us. Like car, human, cat and PC etc.Every objects have some properties e.g a car has properties like color, model, type, Engine Power height, width etc. Almost all car have same properties but these may differ from car to car. And every object shows or posses some behavior or perform some function. This behavior of object is described with methods.

e.g. a car may have methods like car starts, car stops and car moves etc. Similarly an human can eat, watch,walk all these are functions or methods performed by the human.

An object of same type almost have same methods but these are applied at different times.

Example of objects:

Object Name: CAR

Properties of Car.

Car Name :  Toyota   
Car Width :  3.5 feet
Car Length: 8 feet
Car Height: 5 feet
Car Color: White
Car Model: GLI 800
Car Weight: 850Kg

Car Methods

Car Starts
Car Stops
Car Moves

Object Name: Human

Name: Naveed
Father Name: Muhammad Iqbal
Complextion: Fair
Height: 6 feet
Weight: 73Kg

Human Methods

Eat
Sleep
Walk
Talk

Above is the General concept of the objects in real life.

In JavaScript an object can be defined as

var car = {type:"Toyota", model:"Gli800", color:"white"};

Similary.

var human = {
  Name:"Naveed",
  FatherName:"Muhammad Iqbal",
  age:50,
  Complextion:"Fair"
};


Above two statements creates objects of type Car and person.

Objects properties in JavaScript are defined as Name:Values pairs and can be accessed and as well as  assigned as

objectName.propertyName

or

objectName["propertyName"]

for example
  
human.Name;

and  

human["Name"];


Methods in JavaScript

Methods are actions which are defined as like properties in object decalaration For example in below
example fullName is functions defined inside the Object decalarion to Access the Name and Father
Name of the object human


var human = {
  Name:"Naveed",
  FatherName:"Muhammad Iqbal",
  age:50,
  Complextion:"Fair",
  fullName : function() {
    return this.Name + " " + this.FatherName;
  }
};

The this Keyword

In a function definition, this refers to the "owner" of the function.

In the example above, this is the person object that "owns" the fullName function.

In other words, this.Name means the FatherName property of this object.

Objects methods can be accessed

objectName.methodName()

For example in above case

name = human.fullName();