Topic
HTML, CSS, and JavaScript are the languages. The APIs are what the browser actually hands you to build with — the component model, the network, storage, and the observers that tell you what the page is doing. This section works through them one at a time.
The platform's own component model: custom elements, shadow DOM, templates and slots, and the lifecycle that ties them together. Nine steps, each with a live demo you can open and take apart.
Nine steps from what a plain <form> already does, through Ajax, XHR, and fetch, to the shapes that are not a request and a response. The client half of the story: what falls back, what is worth sending, and whether the answer can be trusted.
The browser's native reactivity, and the reason any client-side code runs at all. Seven steps from the three ways to bind a handler, through flow and delegation, to custom events and taming high-frequency streams. Start here before the DOM series — events work without the tree, but working the tree needs events.
Markup maps bidirectionally to objects; select the nodes, effect the change. Nine steps from the parse tree through selection, traversal, modification, creation, and destruction, ending with geometry, observers, and an honest accounting of the libraries that abstract it all.
Web Storage, IndexedDB, and the cache: what persists, where, for how long, and who else can read it.