Inside this article, you will find a clear definition of What is JavaScript Used for in Web Development. JavaScript is similarly applied to your HTML page to CSS. Whereas CSS uses <link> elements to apply external stylesheets and <style> elements to apply internal stylesheets to HTML, JavaScript only needs one friend in the world of HTML — the <script> element. Let’s learn how this works.
JavaScript is mainly used for web-based applications and web browsers. But JavaScript is also used beyond the Web in software, servers and embedded hardware controls. In previous article we clearly define what is JavaScript.

It is the third layer of the layer cake of standard web technologies, two of which (HTML and CSS) we have covered in much more detail in other parts of the Learning Area.
Let’s take a simple text label as an example. We can mark it up using HTML to give it structure and purpose:
<p> Item 1 : Apple </p>

Then we can add some CSS into the mix to get it looking nice:
p {
font-family: ‘Constantia’, helvetica, sans-serif;
letter-spacing: 1px;
text-transform: uppercase;
text-align: center;
border: 2px solid rgba(0,0,200,0.6);
background: rgba(0,0,200,0.3);
color: rgba(0,0,200,0.6);
box-shadow: 1px 1px 2px rgba(0,0,200,0.4);
border-radius: 10px;
padding: 3px 10px;
display: inline-block;
cursor: pointer;
}

At last, we can add some JavaScript to implement dynamic behavior:
const para = document.querySelector(‘p’);
para.addEventListener(‘click’, updateName);
function updateName() {
const name = prompt(‘Enter a new name’);
para.textContent = `Item 1: ${name}` ;
}

JavaScript can do a lot more than this.
While others emphasize that JavaScript is the only programming language the browsers can understand, this doesn’t answer, why JavaScript isn’t being used for other tasks than web development. Well, first of all, JavaScript was created to work in the browser. Historically, it was built as a scripting language for Netscape Navigator. So, it still serves its purpose – JavaScript is the scripting language for all browsers now.
Other experts here correctly remember NodeJS as the most famous way of running JS outside of the browser. Sadly though, NodeJS uses the source code of the V8 engine – a programming technology that executes JavaScript in the Chrome/Chromium family of browsers (and all their numerous descendants). So, while being a technology not directly related to web development (eg I wrote numerous automation tools in NodeJS that were far from web development), NodeJS is still somehow related to the browser. But Node isn’t the only attempt to run JS outside of the browser. It even isn’t the first successful attempt, nor the only one to survive.
Is JavaScript easy to learn?
JavaScript is a simple and easy-to-learn programming language as compared to other languages such as C++, Ruby, and Python. It is a high-level, interpreted language that can easily be embedded with languages like HTML. If you want to learn JavaScript to pursue a career in development, you can find both free and paid courses over the internet. W3schools.com is among the best online tutorials to learn JavaScript.
JavaScript is an open source and cross-platform language and therefore mostly used for creating network-centric applications. Nowadays it has become an inseparable part of the core technologies of the internet. JavaScript is used in web technologies to make web pages interactive. Along with HTML and CSS, JavaScript is widely used in web servers and databases. Hence its wide popularity among these kinds of websites. In order to begin with JavaScript, you can use any simple text editor such as Notepad.