IntersectionObserverについて - Qiita

const io = new IntersectionObserver(function(entries) { entries.forEach(entry => { }) }) document.querySelectorAll('.item').forEach(item => { io.observe(item); }) const options = { root: null, rootMargin: "-100px 0px 0px 0px", threshold:0 } const io = new IntersectionObserver(function(entries) { entries.forEach(entry => { if(entry.isIntersecting){ entry.target.classList.add('inview'); }else { entr