当div被移除时添加效果

.fade-out {
  opacity: 0;
  transition: opacity 0.5s ease;
}

var div = document.getElementById('myDiv');
div.classList.add('fade-out');
div.addEventListener('transitionend', function() {
  div.remove();
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/3.9.1/gsap.min.js"></script>

var div = document.getElementById('myDiv');
gsap.to(div, {opacity: 0, duration: 0.5, onComplete: function() {
  div.remove();
}});