如何在滚动页面时隐藏移动设备中的div

@media only screen and (max-width: 768px) {
  .mobile-div {
    display: none;
  }
}

window.addEventListener('scroll', function() {
  var mobileDiv = document.querySelector('.mobile-div');
  if (window.innerWidth <= 768 && mobileDiv) {
    if (window.scrollY > 100) {
      mobileDiv.style.display = 'none';
    } else {
      mobileDiv.style.display = 'block';
    }
  }
});