What is the difference between var and let in js

Question

So I know you can use var.X and let X= to create a variable named X but what is the difference? Pls help😄

Answer 1

Try searching on search bar before posting a question.
https://www.sololearn.com/Discuss/3307764/?ref=app

Answer 2

Quoting from Javascript Intermediate:
"Unlike the var keyword, which defines a variable globally, or locally to an entire function regardless of block scope, let allows you to declare variables that are limited in scope to the block, statement, or expression in which they are used."

Answer 3

do you mean
var X = document.getElementById("x")
?
there must be no "." between var and X.

Answer 4

Thank you

Answer 5

Can I use var.X. With document.getElementById

Answer 6

Oh

Answer 7

That is what i mean but i just thought you still had to use dot notation

Answer 8

Redeclare
var x = 2;
var x = 3;

/* The variable x is first declared ati store 2, the updated to store 3.. this syntax will be correct. */

let x = 4;
let x = 5;

/* This will give a syntax error you cannot redeclare an already declared variable you just have to update it like x= 5 */

Scope

for (var i = 0; i < 5; i++) {
console.log(i) /* this will return results
1
2
3
4
*/
}

console.log(i) //this will return 5

for (var j = 0; j < 5; j++) {
console.log(j) /* this will return results
1
2
3
4
*/
}

console.log(j) /* this will give a reference error stating j is not defined */

From this we can see that let is block specific which means that a variable declared with let is only accessible via the block in which it was originally declared in, unlike var which was accessed outside the loop which tells us it's not block specific but more general