Can an html element have multiple ids?

Question

I understand that an id must be unique within an HTML/XHTML page.

My question is, for a given element, can I assign multiple ids to it?

Answer 1

Nay.

https://www.w3.org/TR/2011/WD-html5-20110525/elements.html#the-id-attribute

The value must not contain any space characters.

id="a b" <-- find the space character in that VaLuE.

That said, you can style multiple IDs. But if you're following spec, the answer is no.