“HTML5 Differences from HTML4” outlines the changes in the HTML5 specification compared to HTML4. This document, produced by the HTML Working Group, is a draft for the W3C Working Group Note. It emphasizes the need for interoperability, improved markup, and new APIs for emerging web applications. The HTML syntax, which is largely compatible with HTML4 and XHTML1, requires a doctype declaration for standards mode rendering. New elements and attributes have been introduced to enhance structure and functionality, such as
https://www.w3.org/TR/html5-diff/