What is JavaScript?

Software engineers use a whole slew of languages to build mobile applications, web applications, and websites. JavaScript is one of those languages. It’s been around for years. Despite its age, (which, by the Internet’s standards, is pretty old!) JavaScript continues to be a must-know for any engineer. 

Let’s dive more into JavaScript: what it is, how it came to be, and why it’s important for anyone in the industry to know this important widely popular skill.

example of javascript code

What is JavaScript?

JavaScript is aptly named as it’s a scripting language. PHP and Python are other examples of scripting languages. 

JavaScript’s primary and original use was to make web pages more dynamic and interactive. Oftentimes, developers will utilize web frameworks like React, View, or Angular to build complex web apps like Google Docs. These frameworks and libraries themselves are also JavaScript! They make it easier for developers to add, remove, and alter elements on a web page so they can develop new features faster. 

As Career Karma explains, scripting languages use a program known as an interpreter to translate commands and are directly interpreted from source code. They don’t require a compilation step. However, JavaScript in modern browsers use a JIT — just in time compilation. Other programming languages may require a compiler to translate commands into machine code before it can execute those commands. 

Despite the similarity in name, JavaScript and Java are not the same. Engineers typically learn both and use them for different tasks, but we teach Node.js at App Academy which lets JavaScript run on a server, much like many Java applications do. In that respect, they are interchangeable. 

JavaScript coders create features for web pages, where Java coders develop both web- and mobile-based applications using the language. It’s Type Safe, too, so it’s seen as a “safer” programming language as there is less room for type errors.

When and How Was JavaScript Created?

Longtime software engineers and coding professionals have known Javascript for decades now. It has a storied history — one that explains the JavaScript/Java likeness — that started in the early days of the Internet.

According to auth0, pioneering web company Netscape licensed the original Java language, but many within the organization determined a “lighter” scripting language was also needed for Netscape’s Navigator browser to appeal to a larger breadth of programmers. Netscape contracted Brendan Eich (coined the “father of JavaScript”) to create such a language that would make a then-static web significantly more dynamic.

Eich was under a significant amount of pressure as competitors were in the process of making their own version of a programming language that appealed to designers, animators, and creators. Within a few weeks, JavaScript — at the time, known as Mocha — was prototyped and working. Designed initially to complement Java, the features that were baked into this initial language reached far beyond its initial intention. 

Many of those features are cornerstones of the JavaScript we know today, though new iterations are constantly being released. In fact, the 2021 spec was just recently approved and the 2022 spec is currently getting drafted.

What Can You Do With JavaScript?

JavaScript is sort of the icing on the cake for programmers. In some cases, you write JavaScript code to implement dynamic elements that make things move, jump, or scroll. Very few web pages, if any, don’t incorporate these elements in some way, so it’s definitely a must-know skill (or, at the very least, something like JavaScript is) for all engineers. 

JavaScript is also a programming language in its own right. It does a lot of the things other languages like, say, Python can. Make Use Of lists these as:

  • Store and retrieve data values
  • Declare variables
  • Define objects and classes
  • Load and use external modules
  • Write event handlers that respond to click events
  • Write server code
  • Define and invoke functions

Unfortunately, JavaScript — as many other languages are — is subject to use by hackers and ransomware creators. In many cases, JavaScript is used for computer exploits. An exploit takes advantage of a weakness in an operating system, application or any other software code (BullGuard).

How Does JavaScript Work?

JavaScript is “Just in Time Compiled”. That means, when JavaScript runs on a computer, it’s actually being run through a fancy program called a runtime or an engine. One of the most popular JavaScript engines is the open-source V8 engine (it belongs to Google).

JavaScript code is written a lot like its muses, Java and the C family of languages. It has variables, objects, and functions and scoping mechanisms based on the Call Stack. The Call Stack is a data structure that shows where you’re currently at in the program. JavaScript code can only do one thing at a time. 

javascript flowchart for v8 google

This engine is an incredibly complex piece of software, but you don’t need to know how it works or install it to get started with JavaScript. Instead, you have a JavaScript engine inside the very web browser you’re using to view this page. All it takes is a text file with the extension .js and you can get started writing and running. 

Because of the high level of JavaScript, though, it has many unique features not found in lower-level programs; things like treating functions as first-class citizens, which means they can act just like variables do in other languages, and a dynamic nature of adding new code to a program dynamically instead of needing everything defined during a compile phase. 

Examples of JavaScript on the Web

Nearly every major website uses JavaScript to some degree. This includes Google, YouTube, Amazon, LinkedIn, eBay, Twitter, and Facebook, among others. 

Because of how dynamic and interactive JavaScript is, there are endless cool examples of it online. Engaging elements make a web page more interesting and memorable.

Filippo Bello.

Fillippo Bello

Italian-based design agency Adoratorio brought 3-D artist Filippo Bello’s brand to life by creating depth and transition and zoom effects that paid homage to the artists’ medium. 


residente - what is javascript example - app academy

Residente is a musical artist who uses his webpage to interactively display his travels, location, and what he’s working on. Users can scroll around the map to read stories and see photos and videos from everywhere he’s been.



Created to celebrate French cycling culture (Tour de France included), this graphic design project feels seamless as you scroll through different variations of bicycles, sceneries, and color schemes. It was built using JavaScript to create whimsical interaction for the user.

Ways to Learn JavaScript

Like any programming language, JavaScript requires practice and an understanding of key principles. Luckily, anyone with a text editor installed on their computer (or the default ones that come with your particular machine) can start writing Javascript code that can be executed on a web browser. That’s not what software engineers do on the job, but it works for those who are trying to teach themselves the language or simply want to try their hand at writing a few lines of code.

There are also countless free and affordable courses available for learning JavaScript. One of those happens to be our own free program, App Academy Open. It doesn’t cost you anything, and you can learn important other skills and languages in addition to JavaScript, if you so choose. You’re also able to pick the particular parts of the course you’re most interested in — Javascript being one of those in particular.

There are other courses that will teach you JavaScript on its own, including the Modern Javascript Tutorial and Tutorial Republic. You can be a Javascript developer with enough knowledge of the language, but it’s also important to grow your repertoire of languages if you want to go into broader web development or software engineering.

In order to broaden that knowledge, a bootcamp is the sure-fire way to land you a job as an engineer, with JavaScript (and other important languages) under your belt. For San Francisco and New York residents, our Campus Hybrid program builds solid programmers in just 16 weeks. For everyone else around the country (and the world, if they can make lecture times!), we offer an Online Immersive mastery-based program; if you don’t get a concept, you can re-do that portion of the curriculum without penalty!

Why You Should Learn JavaScript

According to Payscale, the average salary for Javascript developers is $83,311 per year or $29.82 per hour. Indeed calculated the JavaScript salary standing at $110,673 a year or $47.49 per hour. The average JavaScript salary, according to Salary Expert, is $99,761 per year.

However, at App Academy, we don’t just help students become single-language developers. We teach a world-class, end-to-end software engineering curriculum that gets people jobs. Our Online Immersive graduates typically net $85,000 in their first jobs out of the program, where our Campus Hybrid graduates in New York average around $90,000 and San Franciscans, around $101,000.

JavaScript is a part of our curriculum because it really is that popular. In fact, many companies use it for on-the-spot coding challenges during interviews. It’s beginner-friendly because of that smaller error margin and a bustling online community (think Reddit and Stack Overflow) to lean on for advice while you’re learning. Plus, you don’t need a development environment since JavaScript is already baked into every web browser.

Even better: JavaScript expertise is in-demand — and not just for software engineers. Anyone in marketing, business and data administration, entrepreneurship, or who works on the web in any capacity could benefit from having working JavaScript knowledge on their resume. As tech continues to grow increasingly omnipresent, it won’t be long before JavaScript is a requirement for professionals other than those in web development.

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Written by Courtney Grace

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