An Introduction to JavaScript: Here Is All You Need to Know

JavaScript is an open-source programming language designed for creating web-centric applications. It is lightweight and interpreted which makes it much faster than other languages and is integrated with HTML making it easier to implement in web applications.

In this Introduction to JavaScript article, you will learn all about JavaScript, the backbone of web development, and understand what exactly this language is and why and how this language is used across various fields.

JavaScript is critical for web development, and if you’ve ever thought about choosing that career path, you’d surely have come across this language. And probably, that’s why you are here in the first place.

Here are the topics covered in this Introduction to JavaScript article:

  • Introduction to JavaScript
  • Why JavaScript?
  • What is JavaScript used for?
  • Say “Hello World” in JavaScript
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Introduction to JavaScript

JavaScript is a scripting language that is used to create and manage dynamic web pages, basically anything that moves on your screen without requiring you to refresh your browser. It can be anything from animated graphics to an automatically generated Facebook timeline. 


Fig: JavaScript

When most people get interested in web development, they start with good old HTML and CSS. From there, they move on to JavaScript, which makes sense, because, these three elements together form the backbone of web development.

  • HTML is the structure of your page like the headers, the body text, any images you want to include. It basically defines the contents of a web page.
  • CSS controls how that page looks (it’s what you’ll use to customize fonts, background colors, etc.).
  • JavaScript is the third element. Once you’ve created your structure (HTML) and your aesthetic vibe (CSS), JavaScript makes your site dynamic (automatically updateable).

Why JavaScript?

JavaScript is an essential programming language, almost compulsory to learn for students or software developers that are gravitated towards web development. Wondering why? Here’s the answer:

  • Javascript is the most popular programming language in the world and that makes it a default choice for web development. There are many frameworks available which you can use to create web applications once you have learned JavaScript.
  • JavaScript offers lots of flexibility. You can create stunning and fast web applications with tons of customizations to provide users with the most relevant graphical user interface.
  • JavaScript is now also used in mobile app development, desktop app development, and game development. This opens many possibilities for you as a Javascript developer.
  • Due to the high demand in the industry, there are tons of job growth opportunities and high pay for those who know JavaScript.
  • The incredible thing about Javascript is that you can find tons of frameworks and libraries already developed, which can be used directly in web development. That reduces the development time and enhances the graphical user interface.

What is JavaScript Used For?

JavaScript is used in various fields from the web to servers, and here’s a quick list of the significant areas it’s used in:


Fig: JavaScript applications

  • Web Applications: JavaScript is used for adding interactivity and automation to websites. So, if you want your web application to be anything more than just a static page of contents, you’ll probably need to do some “JavaScript’ing.”
  • Mobile Applications: JavaScript isn’t just for developing web applications; it is also used for developing applications for phones and tablets. With frameworks like React Native, you can develop full-fledged mobile applications with all those fancy animations.
  • Web-based Games: If you’ve ever played a game directly on the web browser, JavaScript was probably used to make that happen.
  • Back-end Web Development: JavaScript has traditionally been used for developing the front-end parts of a web application. However, with the introduction of NodeJS, a prevalent back-end JavaScript framework, things have changed. And now, JavaScript is used for developing the back-end structure also.

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Say “Hello World” in JavaScript

The next step is to write code. Here’s how you can write a simple JavaScript code that prints Hello World on the browser window.



    <script language="javascript" type="text/javascript">

      document.write("Hello World!");




  • JavaScript can be easily integrated into the HTML code, and that’s exactly what’s happening here.
  • For those of you not familiar with HTML, this code might seem a bit unfamiliar. But it is perfectly understandable even to the web development beginners.
  • <html> tag is required to define a HTML web page. <head> tag. The web page contents are defined inside the <body> tag.
  • Any JavaScript that you add to the web page has to be within the <script> tag.
  • document.write is a JavaScript function that writes the contents onto the web page. In this case, it prints “Hello World!” on screen.

While HTML and CSS are absolutely required to code a basic web page, JavaScript is the language that will help you bring that page to life, making it more attractive to the audience. Taking the time to learn JavaScript will help you in the web development world.

Get Ahead of the Curve and Master JavaScript Today

You may be wondering how you can obtain the skills necessary to take advantage of its immense popularity now that you are familiar with JavaScript. You can also enroll in a comprehensive Java Certification Training, which will help you become career-ready upon completion. 

If you’re an aspiring web and mobile developer, JavaScript training will broaden your skills and career horizons. Do you have any questions for us? Please mention it in the comments section and we'll have our experts answer it for you.

About the Author

Taha SufiyanTaha Sufiyan

Taha is a Research Analyst at Simplilearn. He is passionate about building great user interfaces and keeps himself updated on the world of Artificial Intelligence. Taha is also interested in gaming and photography.

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