JavaScript Introduction

• JavaScript makes websites interactive and dynamic.
• It adds behavior and functionality to HTML and CSS pages.
• It powers forms, sliders, menus, notifications, and live updates.

What Is JavaScript?

• JavaScript is a programming language used to create interactive web pages.
• It responds to user actions such as clicks, typing, and form submissions.
• It can exchange data with servers without reloading the full page.

HTML, CSS, and JavaScript

• HTML provides the structure of a webpage.
• CSS controls the design and layout.
• JavaScript adds interactivity and functionality.

Think of a Website as a Car

• HTML is the car's frame.
• CSS is the paint and styling.
• JavaScript is the engine that makes everything work.

Why Is JavaScript Important?

• Make websites respond to users.
• Validating form inputs
• Creating image galleries and sliders
• Building interactive navigation menus
• Displaying popups and notifications
• Updating content without reloading the page
• Creating web applications and games
• Updating an online shopping cart instantly

How Browsers Use JavaScript

1. HTML to build the page structure.
2. CSS to style the page.
3. JavaScript to add functionality.

• The browser reads and runs JavaScript code.
• The page can then react to clicks, keyboard input, and form submissions.

A Brief History of JavaScript

• Brendan Eich created JavaScript in 1995.
• It was created to make websites interactive.
• It is now used for websites, servers, mobile apps, desktop apps, and games.

Your First JavaScript Program

• Hello World is a common first JavaScript program.

console.log("Hello World");

Understanding the Code

• console is a built-in browser object.
• log() is a method used to display information.
• Hello World is a string of text.
• The message appears in the browser console.

Adding JavaScript to a Web Page

• Add JavaScript to an HTML page with the script tag.
• The example displays a popup when the page loads.

<!DOCTYPE html>
<html>
<head>
    <title>My First JavaScript Page</title>
</head>
<body>

    <h1>Welcome to JavaScript</h1>

    <script>
        alert("Hello, Welcome to JavaScript!");
    </script>

</body>
</html>

Where JavaScript Is Used

• Social media platforms
• Online shopping websites
• Video streaming services
• Banking applications
• Educational platforms
• Business dashboards
• Interactive services such as YouTube, Amazon, Facebook, and Netflix

Key Takeaways

• JavaScript adds behavior and interactivity to websites.
• Browsers can run JavaScript directly.
• JavaScript is used for frontend, backend, mobile, desktop, and games.