The elements, their meaning, and the parsing rules that keep the web working.
A grounded tour of what HTML5 genuinely added to the platform, minus the hype.
Separating the genuine platform wins from a decade of HTML5 marketing noise.
Two serializations, one DOM: what XHTML5 really is and when to reach for it.
Marking up inline definitions with dfn and title, and the accessibility caveats that follow.
A practical checklist of the markup mistakes that quietly break pages every single day.
A doctype does not certify a document; conformance and the label are two different things.
Why the short doctype switches on standards mode, and the quirks-mode history behind it.
The inertia keeping projects on HTML 4, and why moving to the living standard is low-risk.