As we know HTML5 is being developed as the next major revision of HTML (Hypertext Markup Language), the core markup language of the World Wide Web.
It introduces a number of new elements and attributes that reflect typical usage on modern Web sites. Some of them are semanticreplacements for common uses of generic block (<div>) and inline (<span>) elements, for example <nav> (website navigation block) and<footer>. Other elements provide new functionality through a standardized interface, such as the <audio> and <video> elements.
Some deprecated elements from HTML 4.01 have been dropped, including purely presentational elements such as <font> and <center>, whose effects are achieved using CSS. There is also a renewed emphasis on the importance of DOM scripting in Web behavior.
The HTML5 syntax is no longer based on SGML despite the similarity of its markup. It has, however, been designed to be backward compatible with common parsing of older versions of HTML. It comes with a new introductory line that looks like an SGML document type declaration,<!DOCTYPE html>, which enables standards-compliant rendering in all browsers that use “DOCTYPE sniffing”.
There are also new APIs, such as:
- The canvas element for immediate mode 2D drawing
- Timed media playback
- Offline storage database
- Document editing
- Cross-document messaging
- Browser history management
- MIME type and protocol handler registration
- Some of the new features are part of HTML5 mainly because there are no volunteers to split HTML5 and maintain separate specifications of these features.
- Error handling