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

134 Mentors

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

72,686 Students

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

104 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

Exercism is a great website

What I like about it is that I am able to solve the challenges in a TDD way working in a environment that I am familiar (my own PC not a browser IDE) and the cherry on the top of the cake is that I have access to code reviews.

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 Thomas Gamble

Thomas Gamble https://github.com/gambtho

Enjoy solving problems and helping others learn. I've written javascript professionally, and also use it for open source projects.
Avatar of Josh Morrow

Josh Morrow https://github.com/jcmorrow

I didn't feel like I understood JS for the first two years or so that I used it professionally. Once I dug into the prototypical inheritance and functions as a first-class object things really started to click, and ever since ES6 came out it's been a favorite language of mine.
Avatar of Mario Catch

Mario Catch https://github.com/mariocatch

Dad, developer, mentor, learner. I also go by trustie in some circles.
Avatar of Pano Papadatos

Pano Papadatos GitHub

I'm a frontend developer in Maryland USA with experience in other areas as well (full stack, games, devOps etc). I am very interested in frontend architecture and user experience and I am most experienced in JavaScript (+ HTML + [S]CSS)
Avatar of Stuart Taylor

Stuart Taylor https://github.com/Bouncey

Tell me and I forget, teach me and I may remember, involve me and I learn.
Avatar of Abdulaziz Ali

Abdulaziz Ali Personal page

Javascript is sexy, and I love its flexibility and universality. I am a full-stack developer who uses javascript for personal and professional projects almost every day and also passionate about open source.
Fun. Challenging. Interesting

Community-sourced JavaScript exercises

These are a few of the 104 exercises on the JavaScript track. You can see all the exercises here.

Variable Length Quantity
medium
bitwise operations
transforming
Difference Of Squares
easy
algorithms
integers
math
loops
Bob
medium
pattern recognition
regular expressions
strings
conditionals
polymorphism
Sieve
medium
integers
recursion
math
conditionals
loops
Secret Handshake
medium
algorithms
arrays
bitwise operations
games
conditionals
loops
Triangle
easy
exception handling
integers
conditionals
loops
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 Josh Goebel

Josh Goebel Blog: Running Blind

I mostly write Ruby & JavaScript (for fun and profit) but I dabble with TypeScript, Elixir, Nim, Arduino, and such.
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