What Is Javascript Used For?

  • 15 mins read

What Is Javascript Used For?

If you’re 25 or older, you’ll remember the early days of the Internet.

It was still considerably basic in the early 00s; some of us even remember watching our first YouTube video, and many of us could probably tell you what that video was (Charlie The Unicorn comes to mind).

Before JavaScript, HTML allowed very simple websites to be hosted on servers. Even early social media, like MySpace, allowed users to hand-code themes with HTML. 

When JavaScript stepped out onto the scene, we finally saw the internet transform into the experience we are familiar with today.

JavaScript is one of the 3 main coding languages, next to its counterparts, HTML and CSS. Established in 1995 by Netscape programmer Brendan Eich, JavaScript is a versatile, modern coding language. The mid-90s showcased a “browser war,” where industry leaders like Netscape and Microsoft went head to head to see who’s boss. 

It wasn’t all sunshine and rainbows for JavaScript at its conception. In its early stages, its low performance levels made programmers weary of relying on the new language. However, its quirks were exactly what made it stand out. Now, programmers hail JavaScript as a fundamental language needed for web development and programming.

Let’s explore the basics and breakdown some of JavaScript’s use cases.

Basic concepts and fundamentals of JavaScript

“Fortunately, JavaScript has some extraordinarily good parts. In JavaScript, there is a beautiful, elegant, highly expressive language that is buried under a steaming pile of good intentions and blunders.”

Douglas Crockford, JavaScript – the Good Parts

Variables, Data Types, And Operators

With JavaScript, control structures help level out a program’s flow. Conditionals are if-else or switch control structures which read values of an expression and perform actions accordingly. Loops (while, do-while, for, for-in, for-of) are exactly what they sound like. 

They perform actions repetitively, on a loop, like repeating your favorite song on Spotify. Jumps (break, continue, labeled statement) trigger a break or jump in a different part of the program. Control structures are important because simplifying systems within programs makes the job of a web developer or programmer much easier.

Scope in JavaScript indicates how accessible variables are in the code, such as functions and objects. Functions can be used by defining them within the scope where the function is sourced. Functions can be defined by the function’s name, parameters to the function, and other statements which define the function in JavaScript terms. Certain functions, called methods, belong to objects. Variables defined within functions must be kept inside those functions. Therefore, broadening the scope of the functions gives you access to those variables. 

Like a physical object, a JavaScript object stands alone, made up of properties and types. The properties of these objects are what define their characteristics. You can place multiple elements into an array, a global object. Arrays help developers during large, complex projects where they may be juggling a number of elements. 

Essentially, arrays are a useful organizational tool. They are like folders placed within a three-ring binder. Web developers love simplifying complex concepts. JavaScript Object Notation (JSON) is a written way to represent things like objects and arrays. JSON can help transfer complex document types across previously incompatible systems.

JavaScript In Web Browsers

The primary advantage of JavaScript in web browsers is its ability to make the user experience interactive and engaging. Much of our modern experience on the internet derives from the capabilities provided by JavaScript. The programming language revolutionized web based pages and applications. 

It was very one-dimensional previously, with little more user interactivity than clicking links and loading new pages. With JavaScript, users saw animation and more customizable content. It began to feel like a 3 dimensional, revolutionary experience.


Events are nested within each other, like a family of birds, instead of being covered by each other. When you click on a child element, each parent element has a corresponding event. It’s a family affair; when events are triggered, they propagate. 

The capturing phase occurs when the outermost element is clicked. Then, the target is activated, triggering any relevant event handlers. Finally, the bubbling phase sees that every involved element receives the event, runs smoothly, and impresses your website’s visitors.

These specific JavaScript intricacies were not so accessible in the early days of HTML. Now, a long-running joke pokes fun at browser pioneer Internet Explorer and its bare-bones capabilities. That’s because most of its contents were remedial in nature. 

As JavaScript continued to develop, browsers matured with it, inspiring us with their features, speed, and presentation. Even the current major social media platforms could not exist without the trial and error of early days forum websites that were coded with HTML and JavaScript while it was far less advanced than it is today. Still, its presence allowed features like online activity visibility. 

These modern luxuries are things people often take for granted because they seem “simple” and commonplace. We do not tend to think of the events, elements, and detailed code that developers create for the applications we use every day.


The profound advancement that JavaScript provided the user experience on the internet with complexities developers needed to accomodate. So, Application Programming Interfaces (APIs) were created to simplify these complexities. Imagine turning on a light in your home. 

You have to flip a switch, press a button, or even use a smartphone app to turn on the light. Very little thought goes into this process for you, as the user. It’s seamless, almost magic in nature since it feels so instantaneous. You don’t need to deal with any complex wiring without an electrician’s license every time you need to use a light in your house. APIs eliminate the need for developers to write complex, low-level code that could cause problems for their project.

Types Of APIs

A browser API is built into the browser, granting you access to the browser and surrounding computer area. With a browser API, you can do things like manipulate browser audio. You simply don’t need to do any heavy-lifting since the API is doing that for you. 

Getting even more specific, a fetch API does just that— fetch data. It will update small details of a page without you needing to reload the entire page. A localStorage API is also just what it sounds like. This is where you can access your website’s local storage. These are great for large websites with decades of data storage because the data stored never expires or auto deletes. 

Conversely, sessionStorage APIs delete your data once you close the session. Finally, a Geolocation API tracks your location based on cell towers and wifi nodes. Think about your Instagram stories. You’ve probably geotagged your favorite brunch spot, music venue, or travel landmark. Millions of people geotag Instagram posts every day.

Pros And Cons Of APIs

APIs have proven to be one of the most useful tools that make web development easier. People have even used APIs to create hobbyist bots that post their favorite song lyrics every hour on social media platforms. However, this has come at an unfortunate cost. 

Recently, Twitter fell under controversy because the accessibility of their free API seemed to be turning away profits. New Twitter CEO Elon Musk combatted this issue by removing the “basic paid tier” API, well-known and loved by hobbyist bot developers, and turning a profit by turning it into a subscription. Thankfully, many lyric bots still stand without subscribing to Twitter’s monthly plans, but adding complexity to an API is a bit redundant.

JavaScript Libraries And Frameworks

In JavaScript, frameworks are like APIs in that they reduce complexity for developers, while libraries mostly focus on code reuse. A framework is pre-written code, like a blueprint, that acts as the basic structure for your project. A library is also pre-written code, but it performs specific, essential tasks instead of laying your foundation.

Popular Libraries

A few libraries have risen in popularity and become the industry standard. They have risen to the top for good reasons, proving their worth after decades of dedicated use by developers. For example, jQuery is an extremely popular first choice for new developers. It’s a wonderful starting point because it’s easy to learn. 

jQuery reduces the amount of hand coding a developer needs to do. It’s also well-tested, with a large community of developers consistently improving its features and user-friendly nature. jQuery has not been lost over time. Netflix, Microsoft, and even Google still trust it for their industry-leading programs. 

Unfortunately, jQuery isn’t a great choice for complicated components or single-page apps. Instead, try Lodash. This consistent, high-performing library is another fan favorite because of its functional programming paradigm. 

Popular applications Slack and Snapchat rely on Lodash. Developers who need to display dates & times in a readable format use Moment.js. Red Robin, Lexus, and the Red Cross trust Moment.js

Front-End Frameworks

As web development evolves with technological advancement, developers need even more tools to simplify their jobs. Front-end frameworks simplify the process of developing user interfaces. 


React is one of the most well-known front-end framework, largely due to the fact that it is owned by Facebook (now Meta). React uses recyclable components of a final interface that a developer assembles to create a complete product. 

During Facebook’s huge spike in user engagement in 2011, software engineer Jordan Walke created React to accommodate the massive wave of user activity. Today, React is the second-most popular framework behind the server-side framework, Node.js— but more on those later.


For single-page projects, Angular remains one of the most popular front-end frameworks. This open-sourced JavaScript framework is written in TypeScript and maintained by Google. This framework is the gold standard for developers, providing a reliable structure for them to work with. 


Vue.js, is hailed among web developers because it lacks a steep learning curve. It is highly customizable and user-friendly, drawing developers across all skill levels to its features. Vue.js encapsulates the potential that frameworks and libraries have to make web developers’ lives easier.

Frameworks and libraries are designed to streamline your web development workflow. Sometimes, they work better than others. Several factors go into the decision-making process when choosing between libraries and frameworks. 

The size and expertise of your team, project size, and security are just key factors that impact your decision. Surprisingly, most projects use a combination of frameworks and libraries— it is not so black and white or one versus the other.

Since frameworks and libraries simplify your work so drastically, it can be easy to lose the learning experience of doing certain tasks by hand. 

Developers should take the time to learn the language, fully immersing themselves in it to produce the best work possible without relying on these tools as a “crutch.” Sometimes, too much of a good thing can result in a slower loading time for your web page.

Server-side JavaScript With Node.js

As mentioned, Node.js is an increasingly popular server-side, open-source framework. It creates fast, reliable applications. Node.js utilizes “Single Threaded Event Loop” architecture to multitask, allowing developers to tackle multiple clients at the same time.

It uses less to do more; Node.js uses its Single Threaded architecture to produce Multi-Threaded results. It’s easy to use, scalable, and maintainable for developers, whether at a novice or expert level. 

Node.js can create a variety of things, including APIs. Namely, it can create REST APIs, which use Representational State Transfer (REST) architecture and communication, which tends to be preferred by developers because it takes up less bandwidth. 

Node.js is a popular choice for Real-Time Applications with WebSocket. You write single code for both client-side and server-side projects. This helps developers save time while efficiently completing projects. Plus, Node.js is notoriously fast as-is, making it a popular choice for developers. You can reuse code, focus on SEO, and handle powerful data making Real-Time Applications on Node.js.

Server-side rendering (SSR) offers clients improved performance, faster load times, improved SEO, social sharing, and social sharing. The goal of SSR is to send fully-rendered pages to your client. You can use Node.js for SSR; the framework is compute-intensive, allowing it to handle asynchronous I/O in parallel in large quantities. 

Mobile App Development With JavaScript

JavaScript was designed to help developers create interactive web pages. Following its original intention, web developers have used JavaScript to create cutting-edge mobile apps. Libraries like React Native have become integral tools for creating mobile apps.

React Native

It’s no surprise that React is one of the most popular libraries among developers. Its modern approach to development makes it easy to create apps for all the top smart devices like phones, tablets, computers, and TVs. React’s user-friendly interface makes it a popular choice for new developers, but experienced ones flock to it for its reliability. PayPal, Reddit, and Discord all rely on React. 


Ionic Development offers a massive catalog of standard elements like cards and buttons. They are easily customizable, helping you create a stunning visual application for iOS or Android. Similarly, their plugins provide seamless interaction with smartphone hardware. Southwest Airlines, H&R Block, and the National Health Service rely on Ionic Development. 


Many web developers have used NativeScript with Angular to create their applications. As suggested by its name, NativeScript is a powerful choice for native applications. The cross-platform capabilities with Angular, JavaScript, and CSS are great for social media, geolocation, gaming, and news apps. Beachy, Traverse LLC, and Monogram all rely on NativeScript.

JavaScript In Other Contexts

We’ve covered most of the bases with JavaScript and its many contexts, but there is always more to learn. Other important, useful contexts should be studied as you continue to learn the language.

Desktop applications with Electron

Developed by GitHub, Electron is another popular open-source software framework. Electron.js has taken the impressive advancements from frameworks like Node.js and pushed them further. 

By simply providing JavaScript with a rich native API, you can create intricate desktop applications with minimal effort and stress. We foresee Electron to only grow in popularity as technological advancements continue to change at a rapid rate. Skype, Discord, and Slack all use Electron.

Game Development

JavaScript can be a great language for game development, depending on your needs. Since it’s relatively easy to understand, many new game developers use it for their first projects. As you take on more complex work, JavaScript is still an excellent choice since libraries and frameworks exist to simplify your workflow. 

You should solidify a firm language understanding to use JavaScript for game development. From there, you can build other resources to create stunning visuals for the game. One of the most popular games of the late 2000s, Bejeweled, was created with JavaScript.

Internet of Things (IoT) And Hardware Programming

Wikipedia defines the Internet of Things (IoT) as, physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other communications networks.” 

JavaScript is often used in building Internet of Things systems. Firstly, this makes sense because JavaScript is excellent at creating event-driven applications. Plus, it’s great at memory management. Its garbage-collecting mechanism keeps memory use stable while eliminating the need to use the garbage collector too frequently. Moreover, it’s open-sourced; a heightened sense of creativity is needed for IoT software, hardware, and network solutions.

Machine Learning With TensorFlow.js

According to TensorFlow.org, “TensorFlow.js is a library for machine learning in JavaScript.” You can use it to run existing models, retrain existing models, and develop Machine Learning (ML) with JavaScript. Huge tech companies like Twitter use it to train and deploy ML within a browser. Tensorflow.js allows developers to run deep neural networks, often for image classification and natural language processing. Its power, debugging capabilities, and large community make it a popular choice for developers.


What is Javascript in short answer?

Simply put, JavaScript is an open-sourced scripting language that was designed to create a more interactive user experience for web pages.

What is the difference between Java and JavaScript?

It’s all in the name; JavaScript is a scripting language, while Java is a programming language. JavaScript pages are ran on browsers, while Java applications can be run on virtual machines or browsers. Both have a number of notable pros and cons.

Is it difficult to learn JavaScript?

Surprisingly, no! JavaScript is actually one of the easiest programming languages to learn. It’s a great starting place for new web developers who want to learn a programming language.

How long will it take to learn JavaScript?

The learning time for JavaScript varies per-person. On average, most people can learn JavaScript within six to nine months.