JAVASCRIPT

difference between var and let

var is function scoped and let is block scoped. Let's say you have:
function understanding_var() {
	if (1 == 1) {
    	var x = 5;
        console.log('the value of x inside the if statement is ' + x);
    }
    console.log(x);
} 
//output: the value of x inside the if statement is 5
		  5

function understanding_let() {
	if (1 == 1) {
    	let x = 5;
        console.log('the value of x inside the if statement is ' + x);
    }
    console.log(x);
} 
//output: the value of x inside the if statement is 5
		  Uncaught ReferenceError: x is not defined
          
var is defined throughout the entire function, even if it's inside the if 
statement, but the scope of let is always within the curly braces, not outside
it, even if the conditional statement is inside the function.

difference between let and var in javascript

//let
1. It's used in block-scoped.
2. It does not allow to redeclare variables.	
3. Hoisting does not occur in let.
// var 
1. It's used in function scoped.
2. It allows to redeclare variables.
3. Hoisting occurs in var.

difference let and var

------------------Differences------------------		var			let
Global Scope										Yes			No
Can be changed outside statement where made in		Yes			No
Block Scope											No			Yes

let and var difference

function run() {
  var foo = "Foo";
  let bar = "Bar";

  console.log(foo, bar);

  {
    let baz = "Bazz";
    console.log(baz);
  }

  console.log(baz); // ReferenceError
}

run();

difference between "let" and "var"?

In simple words 'var' is function scoped and 'let' is block scoped