HTML 5 Programming and Web development/HTML 5 Doctype
The HTML 5 Document Type Definition (Doctype) is used to identify the type of markup document. conventionally doctypes are written like this
<!doctype root-element PUBLIC [FPI] [URI]>
Where in this case the root-element would be HTML.FPI stands for formal public identifier.
However in HTML 5 the Doctype is just written
Example of doctype in HTML 5
<!doctype html> <html> <head> </head> <body> </body> </html>
The doctype must always be at the top of the document.
Document without doctype
Documents without doctype would work in most browsers ,but would not be classified as a valid document.(see Validation).