vars in js code example

Example 1: var javascript

var text = "";
var i;
for (i = 0; i < 5; i++) {
  text += "The number is " + i + "<br>";
}

Example 2: 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 3: 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

Example 4: js var

var x = 0;

function f() {
  var x = y = 1; // x è dichiarata localmente. y invece no!
}
f();

console.log(x, y); // Genera un ReferenceError in strict mode (y non è definita). 0, 1 altrimenti.
// In modalità non-strict mode:
// x è la globale come si ci aspettava
// però, y è uscita fuori dalla funzione!