why javascript variable declared with {} code example

Example 1: javascript declare a variable

//choose the best for your solution
var myVariable = 22; //this can be a string or number. var is globally defined

let myVariable = 22; //this can be a string or number. let is block scoped

const myVariable = 22; //this can be a string or number. const is block scoped and can't be reassigned

Example 2: variables in js

Variables can have anything, you define them as equal to something
    
    eg:   var x = 22
    var statement = 'hello!'
    var isAbool = true 
    
    there are three types of variables:
1. var 
2. let
3. const 

var is a normal variable
let is a variable whose value can be changed eg: let h = 12, h = 10(we changed the value, if you run this, there will be no error)
const is a variable whose value cannot be changed, if you change the value of a const, you will have errors in you code