What's a valid HTML5 document?

Question

I\'ve just been reading the HTML5 author spec. It states that the , and tags are optional

Answer 1

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: