Lesson 6 +10 XP

JavaScript Variables

A variable is a named container for storing data values.

In modern JavaScript, you declare variables with let or const:

let name = "Ada";
let age = 36;
const pi = 3.14;

Keyword	Can change later	Modern choice
`let`	yes	preferred for changing values
`const`	no	preferred when the value never changes
`var`	yes	old way, avoid in new code

Use the assignment operator = to put a value into a variable:

let price = 10;
price = 15; // change the value

Once declared, use the variable name wherever you need the value:

let firstName = "Ada";
let lastName = "Lovelace";
let fullName = firstName + " " + lastName;

Using a variable before declaring it causes an error. Always declare variables before you use them.