HTML 5 is the next planned revision of the Hypertext Markup Language (HTML), which is a set of markup symbols or codes that can be inserted in files intended for display on Web browsers. In 2007, HTML 5 was adopted by the new HTML working group of the World Wide Web Consortium (W3C). This group published the first public draft of HTML 5 in January 2008. Refinements may continue for years before HTML5 becomes a formal recommendation.
HTML 5 is expected to offer numerous improvements over HTML 4, including:
- New parsing rules for enhanced flexibility
- New attributes
- Elimination of outmoded or redundant attributes
- Immediate-mode drawing
- Drag and drop
- Back button management
- Timed media playback
- Offline editing
- Messaging enhancements
- Detailed rules for parsing
- MIME and protocol handler registration
HTML 5 will be designed so that older browsers that do not support it can safely ignore the new constructs, producing legible Web pages in most cases even if the syntax is not compatible.
Elliote Rusty Harold, an Adjunct Professor at Polytechnic University, wrote on IBM's developerWorks pages that HTML 5 will be:
...instantly recognizable to a Web designer frozen in ice in 1999 and thawed today. There are no namespaces or schemas. Elements don't have to be closed. Browsers are forgiving of errors. A p is still a p, and a table is still a table. At the same time, this proverbial unfrozen caveman Web designer would encounter some new and confusing elements. Yes, old friends like div remain, but now HTML includes section, header, footer, and nav as well.
> The W3C has published the technical details of HTML 5.
> The W3C also explains the differences between HTML 4 and HTML 5.
> There's a handy linked index to elements and attributes in the HTML 5 specification.