底部色带不起作用时的滑块悬停效果

#bottom-strip {
  position: fixed;
  bottom: 0;
  height: 50px;
  background-color: #f7f7f7;
  width: 100%;
  z-index: 9999;
}

#slider {
  position: fixed;
  bottom: 0;
  height: 5px;
  background-color: rgba(0, 0, 0, 0.4);
  width: 100%;
  box-shadow: 0px 2px 4px rgba(0, 0, 0, 0.2);
  z-index: 99999;
}

window.addEventListener('scroll', function() {
  var stripHeight = document.getElementById('bottom-strip').clientHeight;
  var pageHeight = document.documentElement.scrollHeight;
  var windowHeight = window.innerHeight;
  var scrollTop = window.pageYOffset || document.documentElement.scrollTop;

  if (pageHeight - (windowHeight + scrollTop) <= stripHeight) {
    document.getElementById('slider').style.display = 'none';
  } else {
    document.getElementById('slider').style.display = 'block';
  }
});