如何为HTML表格添加附件上传功能？有哪些实现方式？

<table>
  <tr>
    <td>文档名称</td>
    <td>附件</td>
  </tr>
  <tr>
    <td>合同</td>
    <td><input type="file" name="contract_attachment"></td>
  </tr>
  <tr>
    <td>发票</td>
    <td><input type="file" name="invoice_attachment"></td>
  </tr>
</table>
<button onclick="uploadFiles()">上传</button>

<script>
function uploadFiles() {
  const contractAttachment = document.querySelector('input[name="contract_attachment"]').files[0];
  const invoiceAttachment = document.querySelector('input[name="invoice_attachment"]').files[0];

  // 使用FormData对象来构建请求体
  const formData = new FormData();
  formData.append('contract', contractAttachment);
  formData.append('invoice', invoiceAttachment);

  // 发送请求
  fetch('/upload', {
    method: 'POST',
    body: formData
  })
  .then(response => response.json())
  .then(data => {
    console.log('上传成功', data);
  })
  .catch(error => {
    console.error('上传失败', error);
  });
}
</script>

<table>
  <thead>
    <tr>
      <th>文档名称</th>
      <th>附件</th>
    </tr>
  </thead>
  <tbody id="file-table-body">
    <tr>
      <td>合同</td>
      <td><input type="file" name="attachments[]"></td>
    </tr>
  </tbody>
</table>
<button onclick="addFileRow()">添加文件</button>
<button onclick="uploadFiles()">上传</button>

<script>
function addFileRow() {
  const tableBody = document.getElementById('file-table-body');
  const newRow = document.createElement('tr');
  newRow.innerHTML = `
    <td>新文档</td>
    <td><input type="file" name="attachments[]"></td>
  `;
  tableBody.appendChild(newRow);
}

function uploadFiles() {
  const attachments = document.querySelectorAll('input[name="attachments[]"]');
  const formData = new FormData();

  attachments.forEach((attachment, index) => {
    if (attachment.files.length > 0) {
      formData.append('attachment_' + index, attachment.files[0]);
    }
  });

  fetch('/upload', {
    method: 'POST',
    body: formData
  })
  .then(response => response.json())
  .then(data => {
    console.log('上传成功', data);
  })
  .catch(error => {
    console.error('上传失败', error);
  });
}
</script>

const express = require('express');
const multer = require('multer');

const app = express();
const upload = multer({ dest: 'uploads/' }); // 指定文件保存目录

app.post('/upload', upload.array('attachments'), (req, res) => {
  // req.files 包含上传的文件信息
  console.log(req.files);
  res.json({ message: '上传成功' });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});