What is JavaScript?

JavaScript is a versatile, high-level programming language that powers the interactive web. It’s one of the three core technologies of the World Wide Web, alongside HTML and CSS.

A Brief History

JavaScript was created in just 10 days in 1995 by Brendan Eich at Netscape Communications. Originally named LiveScript, it was quickly renamed to JavaScript as a marketing strategy to capitalize on the popularity of Java at the time.

Fun Fact: Despite the similar name, JavaScript and Java are completely different languages with different use cases and syntax.

Why JavaScript?

JavaScript has become the most popular programming language for several reasons:

1. Universal Browser Support

Every modern web browser has a built-in JavaScript engine, making it the only language that can run natively in browsers.

2. Versatility

JavaScript isn’t limited to browsers anymore:

• Frontend: Interactive websites and web applications
• Backend: Server-side applications with Node.js
• Mobile: Native mobile apps with React Native
• Desktop: Desktop applications with Electron

3. Rich Ecosystem

With npm (Node Package Manager), you have access to over 1 million packages to extend your applications.

4. Active Community

JavaScript has one of the largest and most active developer communities, providing endless resources for learning and problem-solving.

How JavaScript Works

When you visit a website, your browser:

1. Downloads the HTML, CSS, and JavaScript files
2. Parses the HTML to build the page structure
3. Applies CSS styles
4. Executes JavaScript to add interactivity

// Your first JavaScript code!
console.log("Hello, World!");

This simple line of code outputs “Hello, World!” to the browser’s console.

ECMAScript - The Standard

JavaScript follows the ECMAScript specification. Key versions include:

• ES5 (2009): Added strict mode, JSON support
• ES6/ES2015: Major update with classes, modules, arrow functions
• ES2020+: Modern features like optional chaining, nullish coalescing

Today’s JavaScript is far more powerful than its 1995 ancestor!

Key Takeaways

• JavaScript is the language of the web
• It was created in 1995 by Brendan Eich
• It can run in browsers, servers, mobile apps, and more
• ECMAScript is the official specification
• It has a massive ecosystem and community

Now that you understand what JavaScript is, let’s set up your development environment!