It sounds like you're conflating two orthogonal concepts: multiple named clipboard locations, and multiple data types on one clipboard. Both already exist, and

It sounds like you're conflating two orthogonal concepts: multiple named clipboard locations, and multiple data types on one clipboard. Both already exist, and are how clipboards on major platforms have worked for decades. The Javascript interface isn't aware of these distinctions, though I'm not sure I want it to. Web apps like this that abuse one plain text clipboard will abuse multiple richly typed clipboards, too.