[varun_ch]

I actually posted a demo of a modern spin on this here recently: https://news.ycombinator.com/item?id=30569396 :)

Since browsers don't allow websites to detect the link colour, we can just trick the user into telling it for us.

https://varun.ch/history

After posting that, I got some emails from others, and someone shared a cool technique involving detecting how long it takes to paint the link to the screen. https://ndev.tk/visted/

[colejohnson66]

This black square demo didn’t work on my iPhone (iOS 16.1). I obviously have HN in the tab’s history, but it didn’t detect it.

[watermelon0]

Works for me on 16.1.1 with both Safari and Chrome (not that there are that many differences anyways.)

It detected HN and other sites.

[Am4TIfIsER0ppos]

> invisible captcha

Disabling javascript saves the day again?

[varun_ch]

It should also be possible to make a fake CAPTCHA without JavaScript - just a little more clunky: https://news.ycombinator.com/item?id=30576517