There is an HTML attribute that does exactly what you think it should do: <div>I’m visible</div> <div hidden>I’m hidden</div> It even has great browser support. Is it useful? Uhm. Maybe. Not really. Adam Laki likes the semantics of it: If we use the hidden attribute, we make our semantic a little better. Anybody will understand what does a “hidden” attribute means on an element. Monica Dinculescu calls it a lie: the hidden rule is a User Agent style, which means…