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Comment by nine_k | Hacker News Reader

(2) A permission to copy something not rendered in the selection.

(4) To show a dialog showing the actual copied content if the content does not match the rendered visible content of the selection.

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(2) is undefined. What defines "rendered in the selection?" Which clipboard data stream are we even discussing? How far are you going to take the rendered analogy? Is font too small to read, white on white, an invisible font, or similar "rendered?"

(4) is better but it would have to be every single time, because (2) is impossible to define.

(2) is possible to define in practical terms, that is, with a small amount of false positives, and very close to zero amount of false negatives.

It's like spam: a precise closed-form analytical definition is impossible, but spam filters do work.

It's absolutely not a reasonable thing to define and target. The bottom line is the feature is a FEATURE and will continue to exist, so trying to police how far websites take it is ultimately a non-starter.

Browser vendors could hypothetically start adding specific types of exceptions to make certain types of the 'hidden box' trick not work, but that would ultimately mean those website developers simply switch to whatever method works. The problem isn't solved, it's just re-coded.

TLDR: There is NO SOLUTION, because there is NO PROBLEM. The feature works as intended, as written in the spec.

Be careful: just because a feature is working as intended and specified, doesn’t mean that there’s no problem. The spec can be just bad.

(I say this as a matter of how you express such things, not about this particular case. I agree with you in considering there to be no bug here, but rather that this is a serious feature that shouldn’t be messed with—and pretty fundamentally can’t without unravelling substantial foundations of the web platform.)

Think about the reasons why e.g. CORS was invented and implemented, despite XHR requests across domains being a perfectly working feature.

Both of your answers assume there is a simple and easy way to identify what is "visible on screen" - which if you read through the OP, you will understand that is not an achievable concept.

Within a browser, which basically knows where each pixel is rendered?

I suspect that for the great majority of practical cases, it is possible.

Where a definite answer is too hard to achieve, it's safe to err on the side of "not visible".

> I suspect that for the great majority of practical cases, it is possible.

The bad guys aren't going to be using the great majority of practical cases.

My idea is that the minority will be false negatives.

The key principle of security is to deny all, allow a closed subset. Same here: allow what is obviously clear and has no hidden parts, and ask a confirmation for all the rest, legitimate or not.

The browser literally highlights the selection so that seems like a solved problem.

I'm in favor of two-tier system where rich applications require permission for enhanced clipboard events but the average site will just copy what is selected without modification.

>The browser literally highlights the selection so that seems like a solved problem.

It's nowhere close to a solved problem, and is much more complex than this. Give a read through the comments in the OP for a taste of why.

I did; it sounded mostly hand-wavy.

Maybe there are deep reasons why it's impossible, but they are not well presented in the OP, unfortunately.

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