JavaScript Hello World: Here's What You Need To Know

JavaScript as you might already know is an open-source programming language. It is designed for creating web-centric applications. JavaScript is lightweight and interpreted, which makes it much swifter than other languages. Being integrated with HTML, JavaScript is easier to implement in web applications. 

In this ‘JavaScript Hello World’ article, you will be introduced to JavaScript, AKA the backbone of web development. You'll be able to understand this language precisely, along with why and how it is used across various fields. Then, you will get an insight into coding a starter ‘Hello World’ program in JavaScript. This will help in getting a feel of how things are done in JavaScript.

JavaScript is essential for web development. So, if you've ever thought about choosing a career in web development, you'd unquestionably have come across this language. And probably, that's why you are here in the first place. So let's quickly get started without wasting any more time!

Here are the things that we'll be talking about in this article that introduces you to JavaScript:

  • What is JavaScript?
  • Why JavaScript?
  • What is JavaScript used for?
  • JavaScript Hello World Program

What Is 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. These three elements together form the backbone of web development.

For those who are not familiar:

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

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Why JavaScript?

JavaScript is an essential programming language that is almost compulsory for students or software developers gravitated towards web development. Some of the points that validate this statement are:

  • JavaScript is the most popular programming language globally, 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 plenty 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 also used in mobile app development, desktop app development, and game development. This opens numerous possibilities for you, as a JavaScript developer.
  • Due to the high demand in the industry, there are great job growth opportunities and high pay for those who know JavaScript.
  • The incredible thing about JavaScript is that you can find innumerable frameworks and libraries already developed, which can be used directly in web development. This reduces development time and enhances the graphical user interface.

What Is JavaScript Used For?

As discussed above, JavaScript is used in various fields, be it web, mobile, or servers. Here's a quick list of the significant areas JavaScript is 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 "JavaScripting."
  • 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 apps with 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. It is a popular pick when it comes to web-based games.
  • Back-end web development: JavaScript has traditionally been used for developing the front-end parts of a web application. But with the introduction of NodeJS, a common back-end JavaScript framework, things have changed. And now, JavaScript is used for developing the back-end structures also.
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JavaScript Hello World Program

Now that we know quite a bit about JavaScript let's write a simple JavaScript Hello World program that prints "Hello World!" on the browser window.



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

      document.write("Hello World!");




  • As previously discussed, JavaScript can be easily integrated into the HTML code, and that's exactly what's happening here.
  • For those of you who are not familiar with HTML, this code might seem a bit alien. But it is perfectly understandable, even to 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.

We sincerely hope that you are now familiar with JavaScript now, and are excited enough to start learning it right away!

While HTML and CSS are 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 immensely in the web development world and make you a suitable candidate for a job.

Get Ahead of the Curve and Master JavaScript Today

If you're an aspiring web and mobile developer, JavaScript training will broaden your skills and career horizons exponentially. 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. 

Simplilearn offers a comprehensive JavaScript Training Course, which will help you become career-ready upon completion. 

Do you have any questions for us? Please mention it in the comments section of the ‘JavaScript Hello World’ article, and we'll have our experts answer it for you.

About the Author


Simplilearn is one of the world’s leading providers of online training for Digital Marketing, Cloud Computing, Project Management, Data Science, IT, Software Development, and many other emerging technologies.

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