> For the complete documentation index, see [llms.txt](https://demirels-organization.gitbook.io/javascript-tutorial/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://demirels-organization.gitbook.io/javascript-tutorial/variables.md).

# Variables

In JavaScript, a variable is a named storage location that holds a value. Variables are used to store values such as numbers, strings, arrays, and objects, and can be declared and initialized in a number of ways.

Here are some examples of declaring and initializing variables in JavaScript:

```javascript
// Declare a variable with the keyword 'var'
var x;

// Initialize the variable with a value
x = 10;

// Declare and initialize a variable in one line
var y = 20;

// Declare and initialize a variable with the keyword 'let'
let z = 30;

// Declare and initialize a variable with the keyword 'const'
const a = 40;

```

The `var` keyword is used to declare a variable in JavaScript. It is important to note that variables declared with `var` are hoisted to the top of the current scope, which means that they can be accessed before they are declared. The `let` and `const` keywords were introduced in newer versions of JavaScript and behave differently than `var`. Variables declared with `let` can be reassigned, but not redeclared, within the same scope. Variables declared with `const` cannot be reassigned or redeclared within the same scope.

It is a good practice to use `let` or `const` instead of `var` whenever possible, as they provide more control over the behaviour of variables in your code.