This doesn’t seem to work? At least not in firefox. https://codepen.io/flyingfisch/pen/wyjQGP
There’s a lot of browser specific setup and a whole nodejs server included in this. I would not qualify this as “pure” CSS keylogging. Neat stuff though!
The actual keylogging inside is done inside of CSS; you’d still need something to exfiltrate it with.
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It works if you can get style injection on a site already using JS to update the .value, though. (e.g. React)
Sure - but it’s a pretty widely installed one.