JavaScript

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JavaScript is a scripting language, primarily used for creating dynamic websites and programming web servers. It's a very popular language, and supports a variety of programming paradigms.
Join the JavaScript Track
Track mentors

112 Mentors

Our mentors are friendly, experienced JavaScript developers who will help teach you new techniques and tricks.
Track students

47,687 Students

Join thousands of students who have enjoyed learning and improving their skills by taking this track.
Track exercises

101 Exercises

Hundreds of hours have gone into making these exercises fun, useful, and challenging to help you enjoy learning.

About JavaScript

export function hello() {
  return 'Hello, World!';
};

ECMAScript is the standard that defines JavaScript, a programming language that allows web pages to be dynamic. It is an interpreted language, which means that it doesn't need to be compiled: instead the interpreter (such as a web browser) will parse the code and turn it into code that their machine can run - suitable for creating dynamic websites that can run on any browser* on any computer*!

JavaScript is not only for use in the browser. JavaScript runtimes, such as NodeJS and deno allow you to write, launch and serve requests on webservers. Other frameworks, such as Electron use JavaScript to write cross platform applications for Windows, Linux and Mac OS. Mobile app development is also a possibility, utilising react-native, ionic and various others, with expo now allowing to target Android, iOS and the web, all at once.

ECMAScript has grown to be one of the world’s most widely used general purpose programming languages. It is best known as the language embedded in web browsers but has also been widely adopted for server and embedded applications." — ECMA International Language Specification

Starting with the 6th edition (commonly known as ES2015 or ES6) in 2015, a new edition of the standard will be released each year. The 6th edition was a major update which brought many enhancements over ES5, including notably template strings, expressive arrow function syntax, and cleaner syntax for defining classes.

But because new syntax and features are coming to JavaScript each year, support for these changes is often incomplete in current browsers and the latest node. This doesn't mean we can't use it. Tools such as Babel offer transpilation for most features, allowing us to write as if it's the future.

Note: This track supports the latest ECMAScript syntax via Babel and the @babel/preset-env plugin, and new experimental features are enabled with each update of that plugin, matching the release of the specifications. It automatically adapts to your local node installation. This means you don't need to worry about what is and isn't supported.


* There is a small number of browsers that doesn't ship with a JavaScript runtime, or that has disabled JavaScript execution by default.

Join the JavaScript track

A tremendous learning opportunity to explore the depth of your own knowledge

Exercism is fantastic in learning new languages but that is not the extent of it. If you are a "more experienced" programmer you may have encountered impostor syndrome: the idea you don't really know what you think you know. Exercism lets you solve problems and put them in the space of open feedback which is a tremendous learning opportunity to explore the depth of your own knowledge. Even if you have been programming in a language for awhile it is worth checking into Exercism to see where you stand with current implementation practices.

Relaxed. Encouraging. Supportive.

Meet the JavaScript Track mentors

Once you join the JavaScript language track, you will receive support and feedback from our team of mentors. Here are the bios of a few of the mentors of this track.

Avatar of Byron Anderson

Byron Anderson Byron's Programming Blog

Javascript is the language I get to use without asking, so I get to pick and choose to just use 'The Good Parts'!
Avatar of David Jones

David Jones Website

Software engineer and a fan of many programming languages
Avatar of Glory Kim

Glory Kim https://github.com/gkim795

I enjoy being able to help others solve problems and expand their knowledge. I've done some freelance backend work, use javascript for my projects.
Avatar of Koen Wellens

Koen Wellens My blog where I review books.

I've been working with JavaScript for about 6 years now. I think I've come at a level where I can help others.
Avatar of Jamie Preston

Jamie Preston https://github.com/jamiepreston

I've been a software engineer for nearly 10 years but I switched to using javascript as a back end language 3 years ago. It soon became my new favourite language! I love the flexibility and the continued advancements in ECMA Script. I look forward to helping out where I can as a mentor and continuing to learn!
Avatar of Sean Fairchild

Sean Fairchild https://github.com/sfairchild

I'm a senior Ruby dev professionally at my company. I have also worked a lot with JavaScript and most recently lead a team building a React app for one of our clients.
Fun. Challenging. Interesting

Community-sourced JavaScript exercises

These are a few of the 101 exercises on the JavaScript track. You can see all the exercises here.

Secret Handshake
medium
algorithms
arrays
bitwise operations
games
conditionals
loops
Twelve Days
medium
pattern recognition
regular expressions
strings
conditionals
loops
polymorphism
Custom Set
medium
arrays
equality
lists
recursion
sets
conditionals
loops
data structures
Darts
easy
misc
Triangle
easy
exception handling
integers
conditionals
loops
Resistor Color
easy
arrays
strings
Passionate. Knowledgeable. Creative.

Meet the JavaScript Track maintainers

The JavaScript Maintainers are the brains behind the JavaScript Track. They spend their spare time creating interesting and challenging exercises that we can all learn from. We are incredibly grateful for their hard work. Here are the bios of a few of the maintainers of this track.

Avatar of Derk-Jan Karrenbeld

Derk-Jan Karrenbeld My website

All-round programmer, manager and owner of a Dutch software agency specializing in bespoke and tailored code.
Avatar of Tejas Bubane

Tejas Bubane My blog

Primarily a Ruby & Javascript coder, getting better at functional programming, emacs lover.

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Join the JavaScript Track