What HTML5 added to the platform: semantics, media, forms, graphics and APIs.
HTML5 was a major revision that modernized the web platform. It introduced the simplified <!DOCTYPE html>, semantic elements like header, nav, article and footer, native audio and video, the canvas and SVG elements for graphics, new form input types and validation, and a set of JavaScript APIs including local storage, geolocation, drag and drop, and web workers. Many things that previously required plugins or heavy libraries became built-in features.
In interviews, a common question is simply 'what's new in HTML5?', but stronger answers also cover what was removed or deprecated, such as purely presentational tags like font, center and marquee, and the shift toward the HTML Living Standard, which is continuously updated rather than released as numbered versions. Being able to connect each feature to the problem it solved, for example the video element replacing Flash, shows real understanding instead of a memorized list.
What you'll walk away knowing