4 Ways to Declare a JavaScript Variable:

• Using var
• Using let
• Using const
• Using nothing

What are Variables?

Variables are containers for storing data. Like text / Numbers / Dates / Colors and more…

 

JavaScript let/var

 

Sample:

let x = "Bill Gates";
let x = 2000;
// SyntaxError: 'x' has already been declared

var x = "Bill Gates";
var x = 2000;
// No Error

{
let x = 777;
}
// x can NOT be used here

{
var x = 2;
}
// x CAN be used here

var x = 10;
// Here x is 10

{
var x = 2;
// Here x is 2
}

// Here x is 2

 

Sample2: Use Variables with (var)

Sample3: Use Variables with (let)