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Swapnil Banga | 10 Aug, 2023

What Is JavaScript? An Introduction to JavaScript


JavaScript is probably the most popular and widely used programming language around the world. Founded in 1995, it quickly became a must-know language in the programming world. According to Github's 2020 Octoverse Report, 95 percent of the world’s 1.8 billion websites use JavaScript. 

But what is JavaScript? What does JavaScript mean?

This article will cover the JavaScript definition and function so you can learn all about what Javascript can do!

What is JavaScript?

The JavaScript meaning entails a powerful object-oriented scripting language used to create interactive web pages. It was initially designed to run in the browser. Still, today you can build web and mobile applications, real-time applications, video streaming applications, and games with the server-side version of JavaScript called Node.js.

What is JavaScript coding? Here’s a simple example of a JavaScript code:

script type="text/javascript"> 

document.write("JavaScript is a simple language and everyone can learn it"); 


Before you learn JavaScript to develop web pages, you need to have a few basic skills, such as

  • A general understanding of the internet
  • Good knowledge of HTML
  • Programming knowledge

While reading about JavaScript, you probably came across this statement: “JavaScript core language features are defined in a standard called ECMA-262.” Let’s look deeper into this. 

What is ECMAScript?

ECMAScript is a general-purpose programming language embedded in the browsers, but is now widely used for server-side applications. JavaScript in browsers and Node.js on the server-side is a superset of ECMAScript. JavaScript follows and supports all the functionalities of the ECMAScript specification.

What Does Javascript Do?

The possibilities with Javascript greatly exceed HTML and CSS capabilities. Here are a few things you can do with Javascript:

1. Make Web Pages Interactive

Users might get bored of a web page if all they can do is read its contents. Javascript can engage viewers by:

  • Zooming in or out
  • Playing video and audio
  • Showing animations
  • Allowing them to slide through images
  • Revealing information or drop-down menus as viewers click or hover

2. Build Apps

You can use Javascript frameworks, or code libraries, to create apps for both mobile and desktop. With these code libraries, developers can save tons of time on mundane programming tasks to focus their attention on the creative side of development. 

3. Develop Games

Photo of JavaScript code

Developers can create engaging browser games with Javascript. Additionally, newbies to Javascript can use simple game development as a means to get comfortable with the programming language.

Features of JavaScript

Browsers: All popular web browsers support JavaScript, such as Netscape Navigator (beginning with 2.0), Microsoft Internet Explorer (beginning with version 3.0), Firefox, Safari, Opera, and Google Chrome. Browsers have a run-time environment called the Java Virtual Machine. These engines convert the interpreted code into machine language. Different browsers have different engine names/runtime environments such as V8 – in Chrome, SpiderMonkey – in Firefox, Chakra in Microsoft Edge.

Syntax: JavaScript follows the syntax of the C programming language like the curly braces for code blocks, using = for assignments, etc. However, it is just superficially similar to C. JavaScript is a scripting language, unlike C, C++, or Java.

Operating Systems: JavaScript supports many operating systems such as Windows, macOS, Linux, etc.

Data Types: You are not required to declare data types for variables or define methods as public, private, etc.

Client and Server-side objects: Client-side and server-side predefined JavaScript objects are different.  

JavaScript is classified into two components based on the functionality:

Client-Side JavaScript 

This component of JavaScript runs on the browser, allowing an application to have elements on an HTML form. The application responds to user events such as mouse clicks, form input, page navigation to display date and time, dynamic drop-downs, and display alert boxes/popups. 

Below is a sample JavaScript code that displays an alert box when you click the mouse button. 



<script type="text/javascript"> 

function sayHello() { 

 alert("Hello There, JavaScript is easy"); 





<p>Welcome to JavaScript</p> 


<input type="button" value="click" onclick="sayHello()"/> 




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Server-Side JavaScript

This component of JavaScript runs on the server and allows an application to communicate with a database. It also handles an application’s workflow by invoking and responding to calls, or performing file manipulations on a server. HTML pages that use server-side JavaScript code are compiled into bytecode executable files. The web server which has the runtime environment runs the application executables. 

Node.js or Node is an open-source runtime environment to execute JavaScript code outside of a browser. It is an environment built around Chrome’s powerful V8 engine with additional functionalities and features. 

Node is usually used to develop API (Application Programming Interfaces). These services are accessed by the client applications, which could be a web application or a mobile application visible to the user. Back-end services fetch data from a database, send emails, manage files, push notifications, manage workflows, etc. Node is powerful when building real-time applications with huge amounts of data. 

Here are some advantages of Node:

  • Agile: Agile development, i.e., you can develop a quick application prototype.
  • Fast: You can develop highly scalable applications with a faster response time.
  • Trusted: Walmart, Paypal, Uber use Node and have shown significant benefits in quick application development, using fewer resources, and achieving fast response time.
  • Clean: Since it is JavaScript-based code, your application will have a cleaner codebase with both front and back JavaScript code. 
  • Secure and diverse: Being open-source, it has a large ecosystem of libraries that you could use.

Below is a sample Node code. 

function myFirstNode()

console.log(‘My first Node Program’);




Note: Objects such as ‘document’ or ‘window,’ specific to the User Interface, do not exist in Node as it is a back-end environment. Instead, it has its own set of objects for the backend.

JavaScript Frameworks

JavaScript Frameworks Diagram

There are several JavaScript frameworks in the market, including popular ones like Angular, Vue, Svelte, and React. Frameworks provide libraries of reusable code and a structured skeleton to develop applications. Frameworks have defined methodologies for structuring your application, how the components interact, application start-up procedure, etc. 

Frameworks speed up application development, since you can use reusable code instead of rewriting it.  

Frameworks like Angular use Typescript, a superset of JavaScript. All Javascript features exist in typescript, among other features. Typescript is more object-oriented than JavaScript though, as you have concepts like classes, objects, interfaces, access modifiers, and static data type (you don’t need to specify the variable datatype in your code).

Learn more: 10 Best JavaScript Frameworks to Use


What is JavaScript? It’s a scripting language that helps you create engaging, creative content. If you want to pursue a career in web development, you’ll need to know this job-securing programming language. 

The opportunities for JavaScript coders and professionals are abundant, and the scope for growth is immense. 

Do you want to expand your knowledge of JavaScript? Why not try take a course to continue your learning journey?

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By Swapnil Banga

Software engineer, hardware enthusiast, writer by avocation and a gamer. Swapnil has been working on Hackr for a large part of his career. Primarily working on Laravel, he is also the author of our React Native Android app. When not in front of a screen, you will find him devouring a novel or listening to heavy metal.

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