Add option for empty href

[surdu]

I would be nice to have and option similar to allow_hash_href but to disallow empty hrefs.

[iBobik]

Could you please describe a few use-cases where is it needed?

[surdu]

I had generated html and the href was generated using a variable that was empty.

Also, forget to add href to an url ?

[iBobik]

Correct me if I am wrong, but isn't it default now? I expected that if I write something like: <a href=""> html-proofer will fail on it.

[gjtorikian]

In the upcoming 4.x release allow_missing_href now exists for this

[gjtorikian]

For added context: HTML5 spec actually allows for missing hrefs, but I feel like more often than not this omission would be human error. So we go against the spec by default, but you can pass the flag in if you really want to allow missing hrefs.