A JavaScript object is an entity having a state and behaviour (properties and method). For example: car, pen, bike, chair, glass, keyboard, monitor etc.JavaScript is an object-based language. Everything is an object in JavaScript.JavaScript is a template based not class-based. Here, we don't create a class to get the object. But, we direct create objects.

Creating Objects in JavaScript

There are 3 ways to create objects.

1. By object literal

2. By creating an instance of Object directly

3. By using an object constructor

1) JavaScript Object by object literal

syntax:

object={property1:value1,property2:value2.....propertyN:valueN}

As you can see, property and value is separated by : (colon).

example:

<script>  

emp={id:102,name:"Shyam Kumar",salary:40000}  

document.write(emp.id+" "+emp.name+" "+emp.salary);  

</script>

Output :

102 Shyam Kumar 40000

2) By creating instance of Object

syntax:

var objectname=new Object();

Here, new keyword is used to create object.

example:

<script>  

var emp=new Object();  

emp.id=101;  

emp.name="Ravi Malik";  

emp.salary=50000;  

document.write(emp.id+" "+emp.name+" "+emp.salary);  

</script>

Output:

101 Ravi 50000

3) By using an Object constructor

Here, you need to create a function with arguments. Each argument value can be assigned in the current object by using this keyword.

The "this" keyword refers to the current object.

example:

<script>  

function emp(id,name,salary){  

this.id=id;  

this.name=name;  

this.salary=salary;  

}  

e=new emp(103,"Vimal Jaiswal",30000);  

document.write(e.id+" "+e.name+" "+e.salary);  

</script>

Output:

103 Vimal Jaiswal 30000

Defining method in JavaScript Object

We can define method in JavaScript object. But before defining the method, we need to add a property in the function with the same name as a method.

example:

<script>  

function emp(id,name,salary){  

this.id=id;  

this.name=name;  

this.salary=salary;  



this.changeSalary=changeSalary;  

function changeSalary(otherSalary){  

this.salary=otherSalary;  

}  

}  

e=new emp(103,"Sonoo Jaiswal",30000);  

document.write(e.id+" "+e.name+" "+e.salary);  

e.changeSalary(45000);  

document.write("<br>"+e.id+" "+e.name+" "+e.salary);  

</script>

output:

103 Sonoo Jaiswal 30000
103 Sonoo Jaiswal 45000

JavaScript Object Methods

The various methods of Object are as follows: