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

That's interesting, but as far as I know the answer is a firm no. I don't see why you need a nested ID, since you'll usually cross it with another element that has the same nested ID. If you don't there's no point, if you do there's still very little point.