The DOM of HTML DOM APIs lets a script change the page. Everything else a web app does, from fetching and storing data to running threads, playing media, reading sensors and measuring its own speed, goes through the Web APIs the browser exposes to JavaScript.
The chapter opens with the rules these APIs share: specifications, secure contexts, permissions and support. It then tours the API families: network, storage, workers, interface, media, device, security, observers and performance, then graphics, built-in AI and polyfills. It closes with third-party embeds and browser extensions.
What you will learn:
How secure contexts, permissions and user activation gate powerful APIs
Talking to servers with Fetch, streams, WebSocket, WebRTC and WebTransport
Storing data, running workers and building offline-capable apps
Using media, device, security and observer APIs, and measuring Core Web Vitals
Integrating payments, maps and analytics, and building browser extensions