Use [*=" "] to check for forbidden whitespaces

[ffoodd]

A few attributes shouldn't contain any whitespace, such as id or lang (see #396).

@matuzo's clever selector using the contains flag for attribute selector would help a lot. Things to consider:

• Which HTML attributes shouldn't contain whitespace?
• Which current tests could be improved this way?
• Which of whitespaces should be tested? Tricky trick gone too far, maybe?

Quite a big one :)

[ffoodd]

Other way around: should it have its own test, just as invalid nesting? This is syntax, after all.
Or improving current attributes selectors would cover the same?

[matuzo]

For the sake of completeness, it was @Schepp's idea. I just made the demos and tested it. :)

[ffoodd]

Thanks for pointing him out 👍
Everyone will go to the credits page, wouldn't have discover it without your sharing :D

[Dionakra]

Reading the HTML standard, I only found two attributes that may not include whitespaces:

• [id]: The id attribute value must be unique amongst all the IDs in the element's tree and must contain at least one character. The value must not contain any ASCII whitespace.
• map[name]: The name attribute gives the map a name so that it can be referenced. The attribute must be present and must have a non-empty value with no ASCII whitespace

Regarding the lang tag, there is not anything specific about whitespaces. I will write what I found in #396.

[ffoodd]

Well, in fact the RFC mentions that no whitespace should be present in a language tag (2 paragraphs above this anchor) and the spec says "Its value must be a valid BCP 47 language tag" — using "a", so I interpret this as "a single".

As far as I understand, that means lang attribute should not contain whitespace either—am I missing something?

[Dionakra]

You are correct, I didn't read that RFC in detail, this I missed that part. Sorry about that! Will include that check in the #396 as well.

[ffoodd]

No worry, reading specs and RFCs is not a that easy (and probably not everyone's hobby neither!). Your insights and researches are greatly appreciated, thanks a lot ❤️