如何在html中上载文档时添加加载符号

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.loading-symbol {
  border: 16px solid #f3f3f3;
  border-top: 16px solid #3498db;
  border-radius: 50%;
  width: 120px;
  height: 120px;
  animation: spin 2s linear infinite;
}

<div id="loading" class="loading-symbol"></div>

document.getElementById('file-input').addEventListener('change', function() {
  var loadingSymbol = document.getElementById('loading');
  loadingSymbol.style.display = 'block'; // 显示加载符号

  // 执行文件上传操作
  // ...

  // 文件上传完成后隐藏加载符号
  loadingSymbol.style.display = 'none';
});