head ... /head, occurrences on page

Only 1 head element is allowed per HTML5 document.

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

Invalid Syntax
(2 head elements are
present)
1 2 3 4 5 6 7 8 9 10 11 12	<!doctype html> <html> <head> <⁄head> <head> <⁄head> <body> <⁄body> <⁄html>

Invalid Syntax
(2 head elements are
present)
1 2 3 4 5 6 7 8 9 10 11 12	<!doctype html> <html> <head> <⁄head> <body> <⁄body> <head> <⁄head> <⁄html>