1. The concept of headers both for requests as well as responses was introduced .
  2. In earlier versions such headers like GET/POST/HEAD which added extend flexibility are not possible with earlier version .
  3. As TCP connection it allowed single request .
  4. Other than HTML, the content type header made it…



Primitive Datatype

Primitive values and object references are stored in JavaScript programs in different ways.

When a primitive value is assigned to a variable (eg. let toy = ‘ball’), variable is given with the value Directly.

Non-Primitive Datatype

When the variable is assigned with an object, however, things are different. When compared with primitive Datatype it does not assign value to the variable Directly it has only contain reference to it . Here’s an example:

const sebi= {

name: ‘Mehta’,

occupation: ‘Stock Broker’,


With the above code, JavaScript creates the object and stores it in computer memory. The variable sebi does not contain the new object directly, it contains a reference to the memory address that currently stores the object.




The JavaScript window object is the top of the JavaScript Object and represents the browser window. and it is supported by all browsers. All global JavaScript objects , functions, and variables automatically become members of the window object. …



String,Number,Boolean are primitive data types whereas Objects and Arrays are composite data types in JavaScript.

primitive data types are passed in by value

composite data types i.e.., non-primitive data types are passed in by reference

let’s see the basic program of copy by value

let a =2;

let b=a;




Jagan mohan

Strings,Booleans can be classified as primitive data types whereas Arrays and Objects are composite data types