HTML5 is the new standard for HTML

HTML5 has new elements, new attributes, offers full support for CSS3, audio, video, support for 2D and 3D graphics, improved error handling, allows local storage on the client side, offers local SQL database, allows you to build applications web and is independent of the device is running.

Every document begins with HTML5

<!DOCTYPE html>

Example of a document HMTL5 with all the necessary elements:

<!DOCTYPE html> <html>   <head>     <title>Title of document</title>   </head>   <body>     Contents of the document   </body> </html>