I had a very similar idea a while back, except I was measuring onAnimationFrame times with a carefully crafted CSS stylesheet to determine which links were bein

I had a very similar idea a while back, except I was measuring onAnimationFrame times with a carefully crafted CSS stylesheet to determine which links were being painted as :visited automatically and completely hidden from the user. Accuracy varied a lot between computers but in ideal circumstances (only browser running) it would have ~90% accuracy on each of 25 links I was testing against - the test took about 8 secs to run though. Interestingly it never worked particularly well in chrome - chrome seemed to stop painting :visited elements after a certain amount which prevented it from working.