html ... /html, occurrences on page

Only 1 html element is allowed per HTML5 document, right after the doctype declaration.

Examples:

Valid Syntax
(1 html element present)
1 2 3 4 5 6 7 8 9	<!doctype html> <html> <head> <⁄head> <body> <⁄body> <⁄html>

Invalid Syntax
(2 html elements present)
1 2 3 4 5 6 7 8 9 10 11	<!doctype html> <html> <head> <⁄head> <body> <⁄body> <⁄html> <html> <⁄html>