What Do JavaScript Developers Do?

Developers use various programming languages to turn ideas and plans into functional and appealing websites and applications. JavaScript is central to this process, as it creates responsive interactive elements on web pages that greatly enhance user experience. It is so effective that over 95% of websites use it to create dynamic content.

Given the key role of JavaScript in front-end web development, companies actively seek developers proficient in this language. According to a report by DevSkiller, a developer skills testing company, JavaScript is the most in-demand IT skill in 2024, and about 72% of companies are looking for JavaScript developers.

So what exactly do these sought-after developers do when working at JavaScript development companies like BairesDev? First, by distinguishing it from the similar language Java, we will explore the various use cases and end products associated with this versatile programming language.

Java vs JavaScript

Despite the similarity in names, JavaScript is not the same as Java. Java, which is currently the third most popular programming language after JavaScript and Python, is used on over a billion devices as part of Google's Android operating system. Java was released by Sun Microsystems in 1995 and is now owned by Oracle. It is widely used for programming credit cards, Android apps, desktop applications, and enterprise-level applications.

JavaScript was created by a developer at Netscape in the early 1990s. It started as a programming language that allowed the computer to interpret user commands without plugins or code compilation. Initially called 'LiveScript', it was added to Netscape Navigator. Later it was renamed JavaScript to take advantage of the growing popularity of Java at that time.

Similarities:

Both languages are object-oriented, using 'objects' to represent data and methods, unlike procedural programming using a list of instructions.
Both languages can be used for front-end development as well as on the server side.

Differences:

The languages are compiled, written, and executed differently.
JavaScript is fully text-based code, while Java code must be compiled.
JavaScript is loosely typed (variables are not bound to a specific data type), while Java is strongly typed (requires developers to define code variables with data type restrictions).
The languages use different plugins.
JavaScript runs only in a browser, while Java allows creating applications that run on the Java Virtual Machine or in a browser.
JavaScript is more client-side focused, while Java is typically used for server-side work.

Front-End Web Development

Front-end developers use JavaScript in combination with HTML and CSS to create the visible parts of websites and applications that users interact with on their phone, tablet, or computer.

Hypertext Markup Language (HTML) is used to format and style web pages. It controls the structure of the site and allows content to be displayed as text, images, links, and videos. CSS is used to style the content that HTML inserts into web pages. It defines shapes, sizes, colors, and fonts, controlling the appearance of the web page.

JavaScript is a scripting language that developers use to create and control dynamic content, turning web page elements into interactive features. It is involved in everything that updates automatically, such as interactive forms, autocomplete functions, and animated menus, and allows new content to load automatically as users scroll.

Additional features created with JavaScript include:

Forms with input fields that check for errors so users enter correct and complete information in all required fields
Animated images
Personalized greetings based on the time of day
Interactive maps

Back-End Development and Other Uses

Although JavaScript is mainly used for front-end development, it has other applications. Developers use some variants of JavaScript, such as Node.js, in back-end development. In this case, it is used to create and maintain the infrastructure that keeps websites and applications running.

Node.js is an open-source runtime environment that handles server-side code and helps execute the program. It improves speed by utilizing server downtime and an event loop to process requests.

JavaScript is also integrated into Android and iOS systems, as well as Desktop and Hybrid applications. This is possible because JavaScript engines—interpreters that convert JavaScript code into machine code that the CPU can execute—are written in C++ and can be embedded in any C++ application.

Additional End Products

Although the primary product of JavaScript is interactive dynamic websites, developers also use it in other areas of web development, as well as for creating games, mobile and web applications, web servers, and slide presentations.

Web Development

In addition to front-end features like interactive forms and animations, JavaScript allows users to load site content without refreshing the entire page. It also supports external web applications such as Flash, PDF, and widgets.

Games

Developers can use JavaScript and HTML5 to create interactive games with complex graphics and animations that only require a keyboard to play. Libraries like EaseJS offer solutions for handling game graphics and allow developers to combine multiple images into one, reducing server requests and bandwidth requirements. Such actions speed up gameplay.

Mobile Applications

Developers can use JavaScript to create cross-platform mobile applications for iOS, Android, Windows, and Blackberry that load content quickly and support various screen sizes and resolutions. Frameworks like React Native that enable this functionality are typically open-source and maintained by support communities that provide documentation and resources for developers.

Web Applications

Because JavaScript can interact directly with browsers rather than passing messages through servers, it allows developers to build web applications more quickly. When developers use Application Programming Interfaces (APIs) with JavaScript, it enhances functionality and performance. With APIs, applications request only the necessary data, avoiding the storage of unnecessary fields.

Web Servers

Developers can use JavaScript to build web servers using the Node.js framework. This approach is event-driven, so such a web server quickly moves to the next task without transferring large amounts of data. Commands are executed individually in single-threaded processes, reducing errors.

Slide-Based Web Presentations

Developers can use JS libraries like Reveal.js and Bespoke.js to create interactive slide presentations based on web technologies. Users can add images and elements such as bulleted lists, and the slideshows provide responsive scaling to adapt to desktops, mobile devices, and tablets.

JavaScript Developers Are in High Demand

It's no surprise that JavaScript developers are in such high demand, given that companies and individuals expect responsive and interactive web page elements from this language. The need for this level of interactivity is likely to persist, so demand for JavaScript developers will not diminish anytime soon.