The James Webb Telescope has been sending us amazing images of our Universe and objects in our solar system. Do you know how the images are photographed and sent back to Earth?

James Webb Nasa GIF by ESA Webb Space Telescope

The answer is JavaScript! NASA uses JavasScript "to talk" with the James Webb telescope.  

JavaScript is the most used programming language. It's used by 78% of developers to build many applications and is mainly used for web development and mobile applications.

Woman saying the word

Understanding what Javascript is used for will give you insights into the world of computer programming and web development. It might just be the programming language you want to learn!

What JavaScript is used for in web development

the letters JS for JavaScript on a yellow background

JavaScript is used by 98% of all websites.

You can view websites through browsers such as Google Chrome or Firefox. The content is mainly digital, consisting of text, images, video, or audio. A website usually only allows visitors to view content, and interaction is limited.

A website typically uses 3 technologies:

Meme Coding GIF by HostGator showing HTML, CSS and JavaScript with an alligator image

HTML or Hyper Text Markup Language. HTML describes the structure of the website to the browser. For example, HTML allows you to add headings and paragraphs, create links, build tables, and more.

CSS or Cascading Style Sheets: CSS is used to style your website. For example, you can use it to tell the browser the colors, fonts, size, and spacing of your content.

JavaScript is the programming language that allows you to add interactivity. It is the only language that can be inserted directly in the HTML of a page. For example, JavaScript will allow you to add the following:

  • mouse hover effects

  • animations

  • create drop-down menus

  • show and hide menus and information

  • autocompletion

  • slide through a carousel of images

  • zoom in and out of an image

  • play audio or video

  • responsive content or content that changes as you resize the browser window

What JavaScript is used for in web applications

Web applications are accessible through a browser. They provide interactivity and functionality and are used to perform specific tasks.

  • The front-end, or the part the user interacts with, is created using HTML, CSS, and JavaScript.

  • The back-end, or the part of the website you don't see, consists of a server or database coded using JavaScript and/or other programming languages such as C++, Java, or PHP.

Flaticon Icon YouTube

Its easy-to-use navigation and tools are all made possible by JavaScript.

Flaticon Icon Facebook

JavaScript gives you the ability to share images, videos, and messages.

Flaticon Icon LinkedIn

JavaScript allows you to connect with colleagues, do searches, create job alerts, and other features.

Flaticon Icon Google

The ability to search is made possible with JavaScript.

What JavaScript is used for in mobile applications

Most of today's popular mobile apps are built using JavaScript. These apps are designed to run on mobile devices such as smartphones or tablets.

Smartphone displaying apps

Flaticon Icon Uber

JavaScript allows Uber users to request a car to take them to a specific destination with a single click of a button.

Flaticon Icon


JavaScript to allows users to buy discounted products or services.

Flaticon Icon Pinterest

Its internal search engine is built by JavaScript, allowing you to search for ideas on almost anything. You can also organize these ideas on boards.

Flaticon Icon Ebay

Through Javascript, buyers and sellers exchange products through online auctions.

What JavaScript is used for in other areas

JavaScript is used for various applications, like software, hardware controls, and servers.

image of a smartphone, smartwatch, headphones and laptop computer

Flaticon Icon

  • Game Development — JavaScript allows you to create advanced video games that run on browsers.

Flaticon Icon

  • Virtual Reality — You can now use JavaScript to build a virtual reality experience right from your browser!

Flaticon Icon

  • Artificial Intelligence (AI) — JavaScript is used to develop artificial intelligence that can foresee future events.

Reasons to Learn JavaScript

The best thing about JavaScript: there's no need to install any software to start using it! You can run it on your browser. You can also use it to create many different projects!

Ceelo Green stating

Flaticon Icon Easy to Learn

JavaScript is easy to understand, unlike other programming languages. It has a simple syntax, or a set of rules on how characters should be organized for you to start writing simple programs.

Flaticon Icon Great for Beginners

Once you master JavaScript, it will be easy to move on to more complicated programming languages like Java or C++. There's also a large online community that you can turn to for support.

Flaticon Icon Popular

JavaScript is the most popular programming language in the world! As mentioned earlier, it's used by 78% of developers today.

Flaticon Icon Career Possibilities

There is a massive demand for JavaScript developers! According to, the average salary of a JavaScript developer in the US is $115,072.


Erica wants to start learning JavaScript but feels it will be too hard to learn. What steps should Erica take to start learning JavaScript?

Take Action

Nearly every electronic device or website you come across every day uses JavaScript. Without JavaScript, all the websites and mobile apps we have come to love and rely on wouldn't exist!

People sitting in front of a monitor displaying different images

The demand for JavaScript professionals keeps growing! It's currently one of the most sought-after skills in the web development industry.

You can learn to code both front-end and back-end, decide what you like best, and qualify for even more job possibilities!

Learn more about what Javascript is used for and how to use it:


Your feedback matters to us.

This Byte helped me better understand the topic.

Get support to take action on this Byte