Is JavaScript front end or backend? Why does this language remain so well-regarded today?

If you’ve ever found yourself rummaging through blogs and articles about web development, you’ve probably stumbled upon numerous mentions of JavaScript. There are so many programming languages - what’s so special about this one? Well, it’s versatility and ease of use, for starters. Also, to answer the title question straight away - is JavaScript front end or backend? It can be both.

But we bet you want to know more than this dry answer. For example, what does JavaScript do to turn websites and web applications from raw to being worthy interactive residents of the world wide web? How is it typically being used by a modern front-end development company? Keep reading to find out many interesting details about why JavaScript is so important to software development in general.

Where Is JavaScript used?

Before we begin listing various uses of JavaScript and why it’s so cool in the first place, here’s a bit of technical trivia. JavaScript is a lightweight text-based programming language for both client-side and server-side of website and web app development. It’s also interpreted, which means the format in which you write and send the code is pretty much how it will be run and how results will return - no need to compile it into another form.

JavaScript and its uses are frequently mentioned alongside its two “friends” - languages called CSS and HTML. This trio is commonly layered when developing a website. The first layer, HTML, helps build structure and add definition to web content. CSS comes second and adds style to that content, such as colors and fonts. A third layer is JavaScript putting on dynamic updates and the rest of the pizzazz.

But it can do so much more than that. Thanks to various frameworks (which we will discuss later in the article), developers can build web and mobile applications. What’s more, you can use this language to create browser games, which is considered an excellent way for novices to practice their JavaScript skills.

And that’s not all yet. Other important use areas include creating interactive maps of real or imaginary locations, data visualization solutions, virtual reality tools, desktop widgets, web services, and booking systems.

Why is JavaScript such a big deal today?

Among the best frontend technologies to use in the industry today, JavaScript takes up a special place. It’s been around for a while as a handy tool for building web pages ever since the second half of the 1990s. Skipping forward to 2022, virtually 98% of all websites use JavaScript on their client-side.

Here are some of the main benefits of JavaScript that make this programming language especially worthy of adding to your technology stack:

  • Thanks to new frameworks and libraries constantly appearing, JavaScript has gotten so versatile that you can do almost anything with it today;
  • Even if the website was made using an entirely different language, you could still add JavaScript-made stuff to it quite seamlessly;
  • By being around for more than three decades, it has accumulated a lot of fanbase, expertise, resources, and tools to help accomplish many interesting projects;
  • Great user experience for both the developers and people using their products thanks to exceptional responsiveness and various device optimization;
  • It’s fast, has a low learning curve, and can effectively work on any device that supports a browser.

What are some ways JavaScript is applied in the front end?

As we’ve established earlier, Javascript is capable of much more than just being one of the basic tools for both frontend developers and backend developers. Nonetheless, for the sake of this article's adequate length, from this on forward, we'll mainly focus on those front-end and back-end sides of things.

Starting with the front-end application, JavaScript’s primary function here is adding interactive behavior to the web pages during development. In other words, it transforms static pages into those that react to the user’s input by including the following web functionality - here are just a few most popular examples:

  • Adding animations to pages;
  • Inserting drop-down menus;
  • Zooming in or out on a picture;
  • Displaying pop-up windows and dialog boxes;
  • Playing multimedia files, such as audio, video, etc.;
  • Changing the appearance of an element when hovered over;
  • Clicking on something to display or hide the information.

Overall, JavaScript is essential for validating any user input that gets sent to the server. Besides interactivity, JavaScript is also used to build single-page applications that run on just one HTML page, creating a smooth navigation flow and user experience. Since it gets embedded directly in the HTML code to be then interpreted by the running browser, the browser itself can “read” the code and run it.

JavaScript is ultimately vital for frontend development due to its less heavy load on the server (since you validate the input beforehand) and widespread support. By the way, for more exciting frontend-related stuff, be sure to check out our article on the difference between Create React App and Next.js.

What are some ways JavaScript is used for backend processes?

Even though originally, JavaScript was created for browsers only, years of programming evolution brought it to the level where it can now be placed on the server and process requests from those same browsers. And it does it with the help of one special tool - a framework called Node.js, which gives JavaScript a platform for hosting purposes.

Now, Node.js does what just a couple of decades ago was only possible by adding another programming language to the mix, like Ruby on Rails, PHP, Python, etc., which meant more resources to use and more developers to hire. The framework, however, is a runtime environment acting as a small operating system by and of itself and giving an opportunity for a program to run outside of a browser.

But why does JavaScript need it in the first place? Because of something called the JavaScript engine. You see, when the language gets used in the browser, that browser contains an engine to interpret and execute the code in a way the machine can understand. The server doesn’t have it, and that’s why Node.js gets weaved into the picture.

Yet it’s not just the “because we can” approach that transformed JavaScript into a backend tool - the benefits very soon became apparent. For example, the language is quite good at handling large amounts of data, which is usually a given when working with servers and huge databases. It’s also fast, reliable, scalable, and has considerable support based on a vast developer community.

What’s the difference between frontend and backend development?

In web development, front-end (the client-side) and backend ( the server-side) are two sides of the same coin, with the coin being either the website or the web application. The front-end is called the client-side because the code is being run on the user’s computer and displayed on their browser. Backend, however, deals with the code that’s run on the web server.

In a more simplified way, when your browser loads a page, it makes a request to the server to go fetch the data. The server first analyzes that request, retrieves what is asked of it, and then transforms the data so that the browser can easily display it. Now on to the differences between front-end and back-end development.

Front-end development means creating visible parts of websites and web applications - everything users can see and interact with, such as links, buttons, animations, and other web content. At the core of front-end development lies that HTML, CSS, and JavaScript trio we’ve previously described.

Meanwhile, back-end web development deals with the web layer where all the data gets stored and accessed - the databases. Backend developers make sure the server can handle the requests, sort them, and send them back to the front-end, where users can see the result on their screens.

Another critical part of server-side development is ensuring the website runs without a hitch, which means being free of bugs, being able to handle the traffic, as well as managing authentication requests, file downloads and uploads, and data encryption.

Backend vs Frontend
Backend vs Frontend

How do JavaScript frameworks work?

JavaScript frameworks are handy units of code libraries used to accomplish various coding or rendering tasks. Those libraries supply developers with pre-written ready-made JavaScript code they can use to skip numerous coding routines for standard tasks or features.

Let’s break down the differences between libraries and frameworks. While both are pieces of code other developers have written and put out for the rest of us in the field to use, a library is a chunk of pre-written code that you can use anywhere in your project, and it’s up to you where you actually put it.

However, frameworks must be put at the exact pre-defined spot to ensure the structural integrity of your code bases. The framework dictates the flow, not the other way around. Yet it’s not limiting at all - you just have to place it at the right spot, and the framework takes care of the application.

Next, we give you a short overview of some of the most popular JavaScript frameworks for developers today.

React. One of the most popular frameworks in 2022, React, is an open-source library made by Facebook for building responsive user interfaces. It lets you reuse components and constantly has new features coming up.

Vue. Vue.js is also an open-source tool designed to help developers build apps more quickly and efficiently. Great for beginners, Vue’s primary purpose is to complement the features of React and Angular.

Angular. This framework is Google’s creation, used for both frontend and backend purposes. Angular supports Typescript and is great at helping create Progressive Web Apps and Single Page Applications.

jQuery. Another open-source library, jQuery, has been around for almost two decades and is primarily used for building simple applications at first, yet it has the potential to be helpful in much more extensive projects through growing the codebase.

Is Node.JS frontend or backend?

Node.js is probably the most popular JavaScript framework for backend development. It makes way for easy management of server-side data updates and allows to build applications able to handle numerous user requests. The platform acts as a bridge between front-end and back-end development by extending JavaScript’s reach all the way to the server.

To make it even more powerful and versatile, the framework itself has its own frameworks now. One of which, NestJS, for example, was built to incorporate TypeScript, another language placed on top of JavaScript to extend its capabilities, which, in turn, allows a smooth creation of scalable and loosely coupled server-side applications.

Summary

As a highly versatile and adaptable programming language, JavaScript has steadily seeped into many different areas of web and software development. On the client side, it adds interactivity to make web pages look and feel the way we have already become accustomed to. It’s also used for web applications because of its tight connection to browsers.

In recent years, it has also become just as effective in backend development, thanks to the framework called Node.js, and is now used to create web servers in an effortless and straightforward way.

All in all, since it’s a perfect all-rounder of a language, if you’re thinking about entering the world of web building and learning web development, whether it’s front-end, back-end, or both - you should definitely give JavaScript a try.

Serhii Hyliuk

Head of Growth

Head of Growth and Customer Success. I'm interested in design, new tech, fashion, exploring new places and languages. My mission is to make our clients happy.

Head of Growth and Customer Success. I'm interested in design, new tech, fashion, exploring new places and languages. My mission is to make our clients happy.

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