HTML5 is intended as a replacement for HTML4 and XHTML. It is based on usage data and developed through cooperation between the W3C and browser makers. An HTML5 page uses the <!DOCTYPE html> declaration and introduces several new semantic elements like <header>, <nav>, <article>, <aside>, and <footer> to help describe different parts of a page. It also includes new form input types and specialized elements for things like canvas, video, geolocation, and offline web apps.