I see it uses and , which, in fact, are not required. Pages without them pass W3C validation without warnings.
But browsers are supposed to create HEAD and BODY elements if your markup doesn't include them. However some do not: http://www.stevesouders.com/blog/2010/05/12/autohead-my-firs...
This means everyone's code that does `document.getElementsByTagName('head')[0]` will fail in some cases. Because that is rather risky, we decided to retain these optional elements..
The closing tags for and however...