When To Use JavaScript in Web Development

JavaScript is the most widely used programming language globally, and as such, there are many ways to use it in web development. But when should you use JavaScript versus something else?

You should use JavaScript when you need a language that works for front-end and back-end uses. You can use JavaScript to make your web pages interactive, create full-stack web and mobile applications, and develop games. In many cases, JavaScript libraries also make sense to use.

Read on to learn more about when to use JavaScript in web development. This article will discuss the best uses of JavaScript and several of its frameworks and libraries. You’ll see that JavaScript is heavily used in front-end web development and has a lot of power in the back end as well. 

Uses of JavaScript in Web Development

JavaScript is the most popular programming language in web development, so as you can imagine, there are many uses for it. Often developers will use JavaScript when building websites, games, and applications.

JavaScript is a full-stack language, meaning that you can use it both for client-side and server-side applications

Adding Interactivity to Websites

JavaScript allows users to interact with a website, accessing data and changing the display of the site. You can use it to create animations, play audio and video, or make features like a drop-down menu. 

Other uses of JavaScript in interactive websites include:

  • Zooming in on an image when you hover over it
  • Clicking through a carousel of images
  • Changing the color of text when the cursor hovers over it
  • Show or hide menu items when you click on them (accordion-style, hamburger-style, etc.)
  • Displaying a count-down timer that starts, counts, pauses, and stops
  • Checking form fields when you type
  • Submitting a form when you hit enter
  • Adding animations when you scroll

Developing Servers and Server-Side Applications

You can use JavaScript to create server-side applications using a runtime environment like Node.js. You can also use JavaScript and Node.js to build a complete simple server to run your programs. 

Node.js runs very quickly, faster than Ruby, Python, or PHP. You could compare JavaScript running in Node.js to Java or C#. 

It’s beneficial to use Node.js and JavaScript on the back-end because it allows multiple requests simultaneously. Because of this, you can let database calls and network operations happen together in the background while other requests use the main thread. This makes applications with a JavaScript backend very efficient.

Creating Web and Mobile Applications

Another use case for JavaScript is creating web and mobile applications. In both cases, you can use JavaScript in both the front end and the back end to create a data-rich, fully interactive application. 

Many developers who use JavaScript for web and mobile applications will use a JavaScript framework or library. For example, the developers of Netflix and Paypal used Angular to build their applications. Angular is a library that you can use in conjunction with JavaScript to bring extra features and functionality to the end product, and it makes sense to use in many cases.

Web and mobile applications also make sense to build with JavaScript when integrating an application programming interface (API). Integrating an API into your application is a great way to add a layer of rich data without hosting an entire database yourself. It essentially allows you to query another person’s server and retrieve data within your app.

Developing Games

There are many ways to make games with JavaScript, but one of the most common is with the EaselJS library. EaselJS allows you to create games with rich graphics beyond what you can do with vanilla JavaScript alone. That said, there’s a lot you can do with just JavaScript when you pair it with HTML5. 

HTML5 and JavaScript together can power games without you needing any additional plugins like Flash. With these tools, you can create a cross-platform game that you can access without switching devices.

Video: JavaScript is present everywhere

How To Use JavaScript

JavaScript is a powerful programming language that can seem daunting to learn. But you can get started with just a few simple but powerful concepts. 

The most important concepts to understand when using JavaScript for the first time are adding scripts, adding event listeners, and using the console. 

Add Scripts

Adding scripts is the first step you’ll take when writing JavaScript. You can add JavaScript to an HTML page by using a script tag like this:

<script src="nameofscript.js"></script>

Just make sure that the JavaScript file (“nameofscript.js”) exists within the same folder as the HTML file. The src attribute should be set to whatever the script’s name is, including the file path if the file doesn’t exist within the same directory as the HTML file.

Add Event Listeners

One of the ways that you can use JavaScript is by adding event listeners to elements in the HTML. An event refers to an interaction between the user and the browser. There are many kinds of events, including things like clicks, scrolls, and mouse hovers. The function addEventListener allows you to add functionality to an element when a specific event happens.

Examples of things you might use event listeners for include drop-down menus, pop ups, and other interactions where the user performs something on the page, like a click. Event listeners can also tell when a user keys information into a form or when they leave a form field.

Output to the Webpage

There are several ways to output to the webpage using JavaScript. One is to use the document.createElement function, which creates an HTML element and then allows you to manipulate it. You can add event listeners, change the text content or attributes, and then put the element onto the webpage with the appendChild function.

Most developers will create their HTML within an HTML file and not through JavaScript when possible. However, there are times when it makes sense to build your HTML through JavaScript, like when you need to perform some mathematical calculation related to what you need to display.

Use the Console

Using the JavaScript console in the developer tools on your browser is a vital tool for working with JavaScript. It shows you errors in your code, and it gives you a specific line number and file name to demonstrate exactly where you need to look to solve the problem.

You can also use the console.log() function to output messages into the console. This is great for debugging because you can test what parts of your code are executing and when and what data they’re handling.

Video: How to properly use JavaScript Console in Google Chrome

Create Functions

In addition to using built-in functions, you can create custom functions for use in your scripts. You can name functions anything you want and then refer to it by that name when you call it to action.

The way functions work is that you first tell the browser what series of directions, then you tell the browser when to execute the directions. The first step is to define what the function will do, and the second is to call it, or execute it.

Functions usually perform some logic and can also do things like add elements to the page, change the display of elements on a webpage, or otherwise manipulate the DOM. They may or may not return a value. If they do, the value can be stored in a variable or otherwise used elsewhere in the script.

When Should You Use a JavaScript Library or Framework?

There are many JavaScript libraries created by and for web developers. Each adds another layer of functionality to your website or application while still maintaining the basic functionality of JavaScript.


jQuery is a small but very widely used JavaScript library. It simplifies much of JavaScript so that you can write the same scripts with fewer lines of code. jQuery is especially powerful from the perspective of making Ajax requests, an area where JavaScript can be difficult to handle. 

Additionally, jQuery has benefits in terms of cross-browser compatibility. Where JavaScript on its own will break in some browsers when you try to run an incompatible function, jQuery will tell the browser what the next best function is to use and go from there. This makes it much better to rely on when you’re trying to program for multiple browsers.

jQuery is easy to learn if you’re skilled with CSS because it uses the same selectors to capture and target elements. And you can use it in conjunction with vanilla JavaScript in the same script. 


React is a JavaScript framework made for creating applications that render efficiently, changing just a part of the page instead of refreshing when the user interacts with it. It can work server-side in conjunction with Node or stay client-side. 

React is especially good for use with mobile applications, although it’s widely used on the web. Many mobile apps are made using React Native, a version of the framework explicitly made for mobile applications.

I use React daily at work, so I am well immersed in the JavaScript world.

Video: What is React and why should you use it.


Angular is a framework used for integrating data into HTML through JavaScript. It involves modules that define the application and controllers that control it, plus views that dictate how it will display.

In addition, Angular is a great library to use when you need a dynamic web application that responds to user inputs with data. You can use it alongside other libraries to create full, rich applications that make the most of your data.


EaselJS is primarily a game development library made to enhance graphics. With EaselJS, you can make and animate high-performance, interactive two-dimensional content based on HTML5. 

In addition to using EaselJS to create games, you can use it to make data visualizations, generative art, and advertisements. It has no dependencies outside itself, so you can use it along with many other frameworks.


Chart.js makes developing responsive charts and graphics simple. It allows you to create eight different kinds of charts, visually representing the data underlying your application. With Chart.js, you can not only create accurate graphics, but you can also animate them. This library allows you to plot and visualize all kinds of datasets with vastly different scales.

Video: Bulding beautiful chart animations with JavaScript and Chart.js


Parsley is a form validation library that you can use to make your site more secure. It adds front-end validation to your fields so that users cannot submit the forms without passing certain rules that you set. It can also be used when handling Ajax requests and promises. 

Alternatives to JavaScript

When it comes to front-end web development, there is no alternative to JavaScript that compares. You can make web pages with just HTML and CSS, but in modern web environments, you need JavaScript or something very similar to make it interactive.

However, some developers use languages like Typescript, CoffeeScript, and ClojureScript instead of writing in JavaScript. These languages compile, or process, into JavaScript. But the developer writes the precompiled code differently depending on which language they’re using.


Typescript is an object-oriented programming language developed by Microsoft that compiles JavaScript. Some developers prefer Typescript to plain JavaScript because it creates a clean codebase and has great scalability. Typescript eliminates some of the challenges involved in creating large-scale software and applications.

I love using TypeScript for my freelance projects. It adds a layer of security and reduces the number of bugs in your code. Here is an interesting read on the pros vs cons of using TypeScript instead of JavaScript. One of the pros is for example Airbnb able to reduce their number of bugs by 38%. But it also comes with some negatives.


CoffeeScript, like Typescript, is a precompiled object-oriented programming language that compiles into JavaScript. It has similar benefits, like creating a clean codebase. It also makes your code easier to maintain and less prone to errors. The syntax is more consistent in CoffeeScript than it is in regular JavaScript.


ClojureScript is another front-end language that compiles into JavaScript. You can use it to leverage various Clojure libraries and reduce the likelihood of human error in your JavaScript. Because the code goes through compiling before reaching the browser, you’ll be notified of any errors before you execute your code.

Video: TypeScript explained in 100 seconds.


JavaScript is an incredibly useful language in web development. You can use it to create web applications, mobile applications, servers, and games. It’s best used when you need speed, performance, and cross-browser compatibility. Additionally, a major benefit of JavaScript is that you can use it both for front-end and back-end applications