how to declare a variable using a variable in js code example

Example 1: how to write a variable in js

//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

Example 2: javascript variable

var user_name = prompt("Please enter your name:", "Type here");
alert("Hello " + user_name);