js file.size单位

function formatFileSize(bytes) {
  if (bytes === 0) return '0 Bytes';
  const k = 1024;
  const dm = 3;
  const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));
  return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
}

// 假设有一个文件输入元素
const fileInput = document.getElementById('fileInput');
fileInput.addEventListener('change', (event) => {
  const file = event.target.files[0];
  if (file) {
    console.log('File size:', file.size, 'bytes');
    console.log('Formatted file size:', formatFileSize(file.size));
  }
});