JavaScript Tutorial

JavaScript is the programming language of the web. HTML builds the page, CSS makes it look good, and JavaScript makes it do things: react to clicks, check forms, show and hide content, and load new data without reloading the page.

Every modern browser can run JavaScript, so you do not need to install anything to start. You only need a browser and this tutorial.

Why Learn JavaScript?

• It runs on almost every website in the world
• It is the only language that runs directly inside the browser
• With Node.js it also runs on servers, so one language can build a full website
• Frameworks like React, Vue and Angular are all built on JavaScript
• It is one of the most requested skills in web development jobs and freelancing

Try it Yourself

Every complete example has a Try it Yourself button. Click it, change the code and press Run.

<!DOCTYPE html>
<html>
<body>

<h2>My First JavaScript</h2>
<button onclick="document.getElementById('msg').innerHTML = 'Assalam o Alaikum, welcome to JavaScript!'">Click me</button>
<p id="msg"></p>

</body>
</html>

What You Will Learn

• Where to write JavaScript and how to show output
• Variables, data types and operators
• Functions, objects, strings, numbers and arrays
• Conditions and loops to control your program
• Events and the HTML DOM, to change a page while it is open
• Promises, async/await, fetch and JSON
• Modern ES6+ features used in real projects

Exercises and Quiz

Most lessons end with a short exercise, and the last lesson is a quiz on the whole tutorial.

Before and After JavaScript

You should know a little HTML and CSS before you start. After this tutorial, learn TypeScript to write safer JavaScript, or jQuery to see a popular library built on it.