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What is JavaScript Used for?

The Many Applications of This Powerful Language

Before JavaScript was invented in 1994, the world wide web was a lot less dynamic than it is today. The vast majority of pages were just static HTML. JavaScript changed all that by giving developers a tool to not just play with the appearance of web pages but to change their behavior and functionality. 

There have been many other web-based languages over the years, yet JavaScript is the only one that is integrated by default into every major browser. That’s part of why it’s been voted the most popular language in the world for eight years running on StackOverflow’s annual survey of developers. The other reason for its ubiquity is JavaScript’s incredible versatility.

Most of the modern web is built with a combination of HTML, CSS, and JavaScript, but the accessibility and extensibility of JavaScript has helped it find a life outside of the web in diverse applications such as back-end development, machine learning, mobile apps, game development, and more.

What is JavaScript?

Developed originally by Netscape during Web 1.0 in the 90s, JavaScript is a text-based programming language. Specifically, it is a just-in-time (JIT) compiled, multi-paradigm language with dynamic typing (fewer restrictions on variable declarations). 

Thanks to its JIT compiler, JavaScript gets some of the advantages of an interpreted language (e.g. dynamic typing) without giving up the main advantage of compiled code, which is strong error prevention. JavaScript also adheres to the principles of object-oriented programming, a paradigm in which helps developers think more creatively about how to organize information and structure their applications. That’s a big reason why JavaScript is so inherently flexible and adaptable.

Netscape originally designed JavaScript for front-end development as a lightweight language that could make web pages more dynamic and responsive to user interactions. Its initial functionality may have been narrow but developers quickly saw the potential to do more and built out a huge collection of libraries and frameworks that extend its usefulness. Today, it’s used for back-end, mobile, and game development in addition to many web applications.

Which JavaScript Frameworks Are Popular?

  • React JS: Built by Facebook to create interactive user interfaces online
  • jQuery: Designed to simplify interaction with the DOM (Document Object Model), a language-independent interface that impacts HTML documents
  • Express: A lightweight JavaScript back-end framework
  • Angular: First developed by Google in 2016 to create fast-loading Single Page Apps (SPA) and Progressive Web Apps (PWA)
  • Vue.js: Adds features to React and Angular
  • Node.js: Cross-platform server environment

What is JavaScript Best Suited For?

Versatile though it might be, JavaScript isn’t the right choice for every application. What it is very well suited to, however, are these four:

Front-end Web Development

JavaScript is still commonly used for its original purpose, adding interactivity and animation to webpages. Elements such as hover animations, zoom effects, and drop-down menus can improve navigation and the User Experience (UX), which in turn can help website SEO.

  • Search box on
  • Embedded video on
  • Refresh button on
  • Image carousel on

Mobile App Development

Development for some of the biggest apps in the world (including Paypal, LinkedIn, Netflix, and Uber) is done using a JavaScript framework like Node.js, React, React Native, Angular, or Vue.

Mobile developers also like JavaScript because thanks to it they aren’t forced to choose between learning languages popular for Android development (Java or Kotlin) or iOS (Swift or Objective-C). They can instead use mobile JavaScript frameworks like React Native and Ionic and build apps that run on both platforms.

Server-side Development

JavaScript isn’t just powering activity on the front-end, it’s in several frameworks that parse data on the back-end, too. The most popular JavaScript server framework is by far Node.js, a cross-platform, open-source server environment that runs on V8, the JavaScript engine developed by the Chromium Project for Google Chrome.

Game Development

There is an extensive list of games built using JavaScript on GitHub. Most games that run natively in a web browser are built using JavaScript. Traditionally, JavaScript games were thought of as less sophisticated than other types of games, but modern frameworks like Phaser.js are giving developers the tools to create very advanced 3D games with JavaScript.

What Other Applications Use JavaScript?

In addition to server-side applications and web, mobile, and game development, Javascript is also used in Artificial Intelligence (AI) and Machine Learning (ML) projects and Virtual Reality (VR) projects. 

There are VR projects for several popular headsets including those from Meta and Valve using the A-Frame JavaScript VR framework. There are also several VR JavaScript projects on the web that use the WebXR Device API, a 3D rendering standard.

AI projects are being facilitated by Tensorflow.js, a JavaScript library for machine learning. Developers can build and train ML models completely in a JavaScript-powered environment.

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