HTML 5 TutorialsHtml5 What is
The <!DOCTYPE> you must declaration on above <html> tag to html5 page and which is not a html tag. When you write html5 page it tells to browser what version of the markup language.
The doctype in HTML 4.01 required to reference to a DTD, because HTML 4.01 based on SGML format .But HTML5 does not need to reference to a DTD and not based on SGML but need the doctype for browsers.
Note : That the <!DOCTYPE> declaration is case-insensitive.
In the above example doctype have been added for Html sample code.