HTML Complete Course
Build semantic, accessible web pages from your first file to native dialogs, safe embeds and fast loading.
- Beginner
- 25 lessons
- 10 hours
Web development
Courses
CSS Complete Course
Style and lay out modern websites, from your first rule to cascade layers, Grid and scroll-driven animation.
- Beginner
- 34 lessons
- 16 hours
Responsive Web Design
Build pages that work on every screen, from a 320 pixel phone to a wide desktop monitor.
- Beginner
- 13 lessons
- 6 hours
Web Accessibility Essentials
Build and test websites that disabled people can use, from alt text to WCAG 2.2 audits.
- Beginner
- 22 lessons
- 12 hours
JavaScript Complete Course
Learn modern JavaScript from your first script to closures, async code, modules and the event loop, with projects you build as you go.
- Beginner
- 54 lessons
- 23 hours
Tutorials
-
Writing testable, modular JavaScript
Separate logic from the DOM, pure functions, dependency injection and small modules that are easy to test.
-
How JavaScript engines work: parsing, JIT and hidden classes
What V8 and other engines do with your code, optimisation and deoptimisation, and what that means for everyday code.
-
Symbols and well-known symbols
Unique property keys with Symbol, and customising language behaviour with Symbol.iterator and friends.
-
Map, Set, WeakMap and WeakSet
When to use Map and Set instead of objects and arrays, and what the weak versions are for.
-
Cancellation, retries and backoff
Cancel work with AbortController, add timeouts, retry with exponential backoff and avoid race conditions.
-
Regular expressions in JavaScript
Pattern syntax, flags, testing and replacing, named groups, and when a regex is the wrong tool.
-
Designing a small JavaScript library
API design, defaults and options objects, error messages, types, versioning and publishing to npm.
-
Timers: setTimeout, setInterval and requestAnimationFrame
Schedule work, cancel timers, and animate smoothly with requestAnimationFrame.
-
Values and references: copying and mutation bugs
Why changing a copied object changes the original, comparing objects, and writing code that avoids accidental mutation.
-
Prototypes and inheritance
The prototype chain behind objects and classes, Object.create, and how property lookup works.
-
The event loop, tasks and microtasks
How the call stack, task queue and microtask queue decide run order, with exercises.
-
Promise combinators: all, allSettled, race and any
Coordinate several promises, handle partial failure, and set timeouts with race.
-
Iterators and generators
The iteration protocol, making objects iterable, and generator functions for lazy sequences.
-
Event bubbling, capturing and delegation
How events travel through the DOM, stopping propagation, and handling many elements with one listener.
-
Callbacks and asynchronous code
Why JavaScript is asynchronous, callback functions, and the problems that led to promises.
-
Promises
Create and consume promises, chaining with then, error handling with catch, and finally.
-
async and await
Write asynchronous code that reads top to bottom, handle errors with try and catch, and run tasks in parallel.
-
Fetching data with fetch()
Request JSON from an API with fetch, check response status, and show loading and error states.
-
Debugging with the console and DevTools
Read error messages, log effectively, set breakpoints and step through code in browser DevTools.
-
ES modules: import and export
Split code into modules with named and default exports, use modules in the browser, and dynamic import.