Course 01 · Foundation
HTML
Structure you can read.
The document, the elements and the meaning behind them. Everything else on the web is layered on top of this.
0 of 22 lessons finished — nothing yet
The syllabus
22 lessons,
in the order they build on each other.
How the web works
What happens between typing a URL and seeing a page: DNS, HTTP, parsing and the DOM.
The document
Doctype, html, head and body — what a page is made of and how an element is written.
Elements and attributes
Global attributes, boolean attributes, data-*, id and class rules, and what may nest inside what.
Text and meaning
Headings, paragraphs, emphasis, quotes and code: choosing the tag that says what the content is.
Lists
Ordered, unordered and description lists — nesting, numbering and when each one is right.
Links and URLs
Absolute, root-relative and relative paths, anchors, download, rel values and target safety.
Images
Formats, alt text that says something, intrinsic size, lazy loading and layout shift.
Responsive images
srcset, sizes, picture and art direction — letting the browser choose before layout.
Audio and video
Sources, controls, posters, captions, preload and the rules that block autoplay.
Tables
Caption, header cells, scope, spans and a table that survives a phone screen.
Forms and inputs
Labels, names and values, method and action, grouping and what actually gets sent.
Input types
Every type and what it buys you, plus inputmode and the autocomplete tokens worth knowing.
Validation
required, pattern, the constraint validation API, custom messages and why the server still checks.
Semantic layout
header, nav, main, article, section, aside, footer — and when a div is still the right answer.
Interactive elements
details, dialog, popover, progress, meter and output — behaviour without JavaScript.
Embeds and graphics
iframe with sandbox and allow, inline SVG versus img, and where canvas fits.
Accessibility
Names, keyboard order, focus, landmarks and the rule that beats every ARIA attribute.
The head and metadata
Charset, viewport, title, description, canonical, icons and script loading.
SEO and social cards
What search engines actually read, Open Graph, sitemaps, robots and JSON-LD.
Languages and direction
lang, dir, right-to-left layout, hreflang and text that is not English.
Templates and components
The template element, slots, and a first custom element with no framework.
Debugging HTML
The validator, the elements panel, and the symptoms of a tree the browser had to repair.
Keep going
The other courses.
CSS
Selectors, the box model, layout with flexbox and grid, and motion that has a reason to move.
JavaScript
Values, functions, the DOM, events and asynchronous work — written so you can debug it later.
React
Components, state and effects — the model behind most interfaces built today.