Web Components
Every component framework (React, Vue, Lit, Angular) either compiles to or interacts with these primitives. Shadow DOM is how browsers isolate component internals. Understanding the native model prevents framework lock-in.
What It Defines
The browser's native component model: Custom Elements (defining new HTML tags with lifecycle callbacks), Shadow DOM (encapsulated DOM subtrees with scoped styles), HTML Templates (<template> and <slot> elements). Defined across the HTML and DOM living standards.
Canonical (Normative)
Convenient (Practical)
Maintains the living standards for the web platform: HTML, DOM, Fetch, URL, Streams, and more. These are continuously updated living documents, not versioned snapshots.
Related Specs
The spec behind every HTML page, form, and browser API. The canonical reference for how browsers actually parse and process HTML.
Every frontend framework (React, Vue, Svelte) ultimately produces DOM operations. Understanding the event model and tree structure prevents subtle bugs.
CSS drives all visual layout. Key modules: Grid, Flexbox, Custom Properties, Cascade layers, Container Queries. The snapshot identifies what's stable vs experimental.