HTML5
Scope
Creating/editing pages; document structure and metadata; text, links, images, lists, tables, forms, and media; CSS foundations; JavaScript foundations; and HTML5-era browser capabilities.
Durable knowledge
- HTML describes meaning and structure; CSS presents it; JavaScript adds behavior.
- Use headings, landmarks, links, buttons, lists, tables, and forms according to semantics rather than appearance.
- Accessible names, labels, keyboard behavior, alternative text, and logical document order are part of correctness.
- Forms define a data contract: names, types, constraints, method, action, and server-side validation.
- Use tables only for tabular relationships, never general page layout.
- External CSS and JavaScript improve separation, caching, and maintainability.
- Browser APIs require feature/security awareness; storage, media, graphics, and communication APIs have different privacy and compatibility boundaries.
Current-use caution
Some HTML5-era APIs and CSS layout advice have evolved. Prefer semantic HTML, Flexbox/Grid, responsive design, current accessibility practice, and current MDN/browser documentation.