JavaScript Objects

Objects in JavaScript

The objects in JavaScript is a structure that has a state and behavior or we can say properties or method just like, Bike, pen, car, etc.
It is a known fact that JavaScript is an object-based language and every single thing in JavaScript is called an Object.

In JavaScript, class is not created in order to get the object instead, the object is created directly hence, making it a template-based language.

These three ways are followed to create objects in JavaScript:

• Object Literal
• Object Directly (using new keyword)
• Object Constructor (using new keyword)

1. Object by Object literal in JavaScript

Here is the syntax for creating object by Object Literal:

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

Please note that the property and value is separated by : (colon).

Let's understand this method of object creation by this simple example:

<script>
emp={id:101,name:"Radhe Shyam",salary:120000}  
document.write(emp.id+" "+emp.name+" "+emp.salary);   
</script>

2. Object by Object directly

Here is the syntax of creating object directly:

var objectname=new Object();   

Please note that new keyword is used here to create object.

Let's understand the object directly with this example:

<script>
var emp=new Object();  
emp.id=130;  
emp.name="Hello Employee";  
emp.salary=90000;  
document.write(emp.id+" "+emp.name+" "+emp.salary);     
</script>

3. Object Constructor in JavaScript

In this method functions needs to be created with arguments and each argument value can be assigned easily in the current object by the help of this keyword. Please note that ‘this’ keyword is referring to the current object.

Here is an example to understand this easily:

var objectname=new Object();   

Please note that new keyword is used here to create object.

Let's understand the object directly with this example:

<script>
function emp(id,name,salary){  
this.id=id;  
this.name=name;  
this.salary=salary;  
}  
e=new emp(11,"hello hi",65000);    
document.write(e.id+" "+e.name+" "+e.salary);       
</script>

Let's Understand The Defining Method In Javascript

A method can be defined in JavaScript Object but in order to define method a property needs to be added in the function with the same name as of method. Here is an example to explain it better:

<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(10,"oonu aiwal",5000);  
document.write(e.id+" "+e.name+" "+e.salary);  
e.changeSalary(56000);  
document.write("
"+e.id+" "+e.name+" "+e.salary);        
</script>

Object Methods in JavaScript

Here are the following various object methods in JavaScript: