Variables Declaration | Definition | Scope

 Variable Declaration | Definition

Three keywords are used to declare variables in JavaScript :

1.     var 
2.     let
3.     const

1. var keyword: 

        - Global scope

        - can Re-declare

        - can Re-define or reassign the value

        - eg. var a=10;

2. let keyword: 

        - Block scope

        - can not re-declare

        - but can re-assign

        - eg. let a=20; or let a="hello";

3.  const keyword: 

        - Block scope

        - can not re-declare

        - can not re-assign

        - eg. const pi=3.14;

Declaration and Definition

Declaration and Definition