What Is JavaScript and How Is It Used?

From website design to server-side request processing, JavaScript (or JS for short) has an almost staggering array of applications and is present on virtually every website in existence. 

But what is JavaScript exactly, and how is it actually used by amateur site builders, professional developers and everyone in between? Find out to take the first step toward learning JavaScript yourself. 

Quick Links

• What Is JavaScript?
• How Is JavaScript Used?
• How to Learn JavaScript
• Jobs That Use JavaScript

What Is JavaScript?

If you’ve ever interacted with a website, then you likely have JavaScript to thank. And with 98 percent of all sites using JS, chances are you’ve come across it many times before. 

So what is JavaScript? Put simply, it’s a computer scripting language that, along with HTML and CSS, is one of the core technologies of the Web as a whole. 

First invented in 1995 by Mozilla project co-founder Brendan Eich, JavaScript was originally developed for Netscape (yep, the same Netscape browser everyone used throughout the 90s and then immediately forgot about).

While professional web developers can employ advanced JavaScript techniques to create more nuanced results, the language can be broken down into relatively simple building blocks. These include: 

• Variables, which are labeled containers for variable values. 
• Operators, which perform mathematical operations on two values. 
• Functions, which are blocks of JS code designed to accomplish specific tasks. 
• Comments, which allow developers to add notes to their code. 
• Conditionals, which determine whether or not lines of code can be executed. 
• Events, which determine what will happen if a specific event occurs. 

By combining those and other components, developers can use JavaScript to create engaging and interactive content of almost any kind, regardless of their skill level. 

How Is JavaScript Used? 

You already know that JavaScript can be used to create more interactive content, but what does that mean in practice? 

To find out, you’ll need to distinguish between front- and back-end web development. 

Front-End Development

This type of web development deals with the aspects of a website users interact with. In this space, JavaScript affects the designs they see, the buttons they click and the menus they use. 

For instance, JS can be used to display a certain message whenever users click a button. It can even display different messages depending on the number of times a user has clicked. In the following example, the highlighted JS snippet is instructing the page to display a unique message whenever a user clicks more than five times: 

Also included in the realm of front-end development are games, which JavaScript can and is used to create. It’s been used to create well-known games such as 2048, HexGL and more.  

Back-End Development 

While JavaScript is perhaps best-known for its ability to create interactive webpage elements, it’s also a widely-used language for back-end development. 

In short, back-end development is the type of web development used to create and maintain the parts of a website that users don’t come in contact with. For instance, a site’s architecture, scripting and databases all fall under the umbrella of back-end development. 

JavaScript comes into play because it’s ideal for building applications that process user requests and connect to databases, among other things. 

How to Learn JavaScript 

If you’re interested in learning a language as ubiquitous and versatile as JavaScript, you’re not alone. That’s a good thing, because when it comes to learning JS there’s a method available for just about every style of learning:

• Online classes: Whether you prefer learning from your own home, need a flexible schedule or just want to get started ASAP, online JavaScript classes can help. 
• In-person classes: If you learn best in a face-to-face environment, you may be able to do so at a nearby trade school, community college or computer training school. 
• Self-teaching: All about DIY? No problem – using resources like W3Schools, it’s possible to teach yourself JavaScript. 

Want to take your knowledge of JavaScript from a hobby to a career? Certification can help prove your expertise to employers. 

Some of the most useful and respected JS certifications include: 

• The Certified JavaScript Developer certificate from the International JavaScript Institute; 
• The W3Schools JavaScript Certificate from W3Schools
• CIW JavaScript Specialist certification from Certified Internet Web Professional (CIW) 

With any of those certifications under your belt, no potential employer will have doubts about your JavaScript skills. 

Jobs That Use JavaScript

Wondering what types of positions you might be able to land if you learn JavaScript? These are some of the most common: 

• Front-end developer: Create, maintain and improve the user-facing elements of a website.
• Back-end developer: Create, maintain and improve the non-user-facing elements of a website, such as the data strategy and security measures. 
• Full-stack developer: Build and maintain both client- and server-side software using a variety of languages, including JavaScript. 
• Mobile app developer: Build, test and program applications intended for use on mobile devices such as smartphones and tablets. 
• Website designer: Design and optimize the visual elements of a website’s user interface. 

That’s certainly not an exhaustive list, though. And if you choose to learn other languages in addition to JavaScript, you can also qualify to work as a software engineer, system administrator and more. 

JavaScript vs. Java

Wondering about the difference between JavaScript and Java? The answer is just about everything (except for their coffee-inspired names, of course). 

Why? JavaScript is an interpreted language, while Java is a compiled language. In other words, JavaScript is able to execute its instructions directly from a browser, while Java must first be compiled by a server. 

In practice, that means JavaScript is typically used for client-side applications, while Java is used for server-side applications. 

Want to Create Standout Sites? JavaScript Is Worth Your Time

From creating interactive elements on your own personal site to developing back-end applications on a professional level, JavaScript can help you achieve your goals. 

So whether you’re looking to pick up a new hobby or work toward becoming a web developer by trade, JS is one language worth learning.