脚本使横幅在滚动时消失的问题

window.addEventListener('scroll', function() {
  var banner = document.getElementById('banner');
  var bannerPosition = banner.getBoundingClientRect().top;
  var windowHeight = window.innerHeight;
  
  if (bannerPosition < windowHeight) {
    banner.style.display = 'none';
  } else {
    banner.style.display = 'block';
  }
});

@keyframes fade {
  0% { opacity: 1; }
  50% { opacity: 0; }
  100% { opacity: 1; }
}

.banner {
  animation: fade 2s infinite;
}

$(window).scroll(function() {
  var banner = $('#banner');
  var bannerPosition = banner.offset().top;
  var windowHeight = $(window).height();
  
  if (bannerPosition < windowHeight) {
    banner.fadeOut();
  } else {
    banner.fadeIn();
  }
});