declare variable javascript 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: js variables

//Making variables with let:
let numberOfFriends = 1;

//Incrementing:
numberOfFriends += 3; //numberOfFriends is now 4

// Variables with const
const minimumAge = 21; //CANNOT REASSIGN!

//Booleans - true or false values
true;
false;
let isHappy = true;

//Naming Conventions
// Use upper camel-cased names:
let numberOfChickens = 6; //GOOD
// NOT THE JS WAY:
// let number_of_chickens = 6;

Example 3: javascript variable

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

Example 4: how to change a variables value in javascript

var variable = 10;

function start() {
  variable = 20;
}
console.log(variable + 20);

// Answer will be 40 since the variable was changed in the function

Example 5: how to define variable in javascript

var <variable-name>;

var <variable-name> = <value>;

Example 6: javascript define variable

var variable1 = "some variable content";