Variables in JavaScript

Variables are used to store data in a program. In JavaScript, variables are declared using the var keyword.

Here’s how you can declare a variable in JavaScript:

var x; // Declare a variable named x

Once you’ve declared a variable, you can assign a value to it:

x = 10; // Assign the value 10 to the variable x

You can also declare and assign a value to a variable in one line:

var y = 20; // Declare a variable named y and assign the value 20 to it

JavaScript is a dynamically-typed language, which means you don’t need to specify the data type of a variable when you declare it. The data type of a variable is determined by the type of the value it holds. For example:

var name = "John"; // The variable name has a string value
var age = 30; // The variable age has a number value
var isStudent = true; // The variable isStudent has a boolean value

Variables can also be used to store the result of an expression:

var sum = 5 + 10; // The variable sum holds the value 15

It’s important to note that variable names are case-sensitive in JavaScript. This means that name, Name, and NAME are all considered different variables.

Once you’ve declared and assigned a value to a variable, you can use it in your program to perform calculations, make decisions, and more.

That’s a brief introduction to variables in JavaScript. In future tutorials, we’ll explore more advanced concepts, such as scope, hoisting, and the different ways to declare variables in JavaScript.