(sorry, bad title) This was originally filed against the IntersectionObserver spec: https://github.com/w3c/IntersectionObserver/issues/472 STR: 1. go to https://jsfiddle.net/90sw7dhf/ 2. scroll down Expected: in Firefox and Chrome, alternating green and blue divs, infinitely Actual: in Safari TP, green turns blue, then a different shade of blue and that's it. The jsfiddle has a log, and it seems like it's looping forever when trying to log "wow".
<rdar://problem/95038984>
Created attachment 460325 [details] Testcase
In both Chrome and Firefox there's a scroll position jump that happens when the elements are moved around. That might be a side effect of scroll anchoring, which Safari doesn't have. Something similar happens in Firefox if I disable scroll anchoring, and that makes sense; moving the elements changes their intersection, which fires the callbacks, which changes the content.