What is HTML5, and how is it different from HTML 4?

Summary

HTML5 (a W3C Recommendation in 2014, now the WHATWG's HTML Living Standard) modernised HTML for web applications: semantic structure elements, native video and audio, canvas, new form input types with built-in validation, web storage and other APIs, a short <!DOCTYPE html>, and precisely specified, error-tolerant parsing.

Longer Answer

HTML 4.01 (1999) relied on plug-ins such as Flash for video and graphics and on generic divs for page structure. HTML5 added header, nav, main, article, section, aside and footer; video and audio; canvas and inline SVG; input types such as email, date and range with constraint validation; localStorage and sessionStorage; and defined exactly how browsers must parse even broken markup. Since 2019 there are no numbered versions: HTML is a Living Standard, so "HTML5" now simply means modern HTML.

Key Points

• Semantic structure elements.
• Native video, audio and canvas.
• New input types and validation.
• Web storage and APIs.
• Living Standard since 2019.

Deep dive: HTML5 for Beginners: A Short History of HTML

What interviewers look for

Concrete features, not just 'it's newer', and awareness of the Living Standard.

Follow-up questions

• What replaced Flash?
• Will there be an HTML6?