What's a valid HTML5 document?
I've just been reading the HTML5 author spec.
It states that the <html>, <head> and <body> tags are optional.
Does that mean that you can leave them out completely and still have a valid HTML5 document?
If I'm interpreting this correctly, it means this should be completely valid:
<!DOCTYPE html>
<p>Hello!</p>
Is this correct?
You can check out the spec here:
http://dev.w3.org/html5/spec-author-view/syntax.html#syntax
"8.1.2.4 Optional tags" is the bit out about it being OK to omit <html>, <head> and <body>
Answer
The title element is indeed required, but as Jukka Korpela notes, it also must be non-empty. Furthermore, the content model of the title element is:
Text that is not inter-element whitespace.
Therefore, having just a space character in the title element is not considered valid HTML. You can check this in W3C validator.
So, an example of a minimal and valid HTML5 document is the following:
<!doctype html><title>a</title>