问如何在使用javascript将html表格转换为csv时合并或组合单元格

EN

function downloadCSV(csv, filename) {
  var csvFile;
  var downloadLink;

  // CSV file
  csvFile = new Blob([csv], {
    type: "text/csv"
  });

  // Download link
  downloadLink = document.createElement("a");

  // File name
  downloadLink.download = filename;

  // Create a link to the file
  downloadLink.href = window.URL.createObjectURL(csvFile);

  // Hide download link
  downloadLink.style.display = "none";

  // Add the link to DOM
  document.body.appendChild(downloadLink);

  // Click download link
  downloadLink.click();
}

function exportTableToCSV(filename) {
  var csv = [];
  var rows = document.querySelectorAll("table tr");

  for (var i = 0; i < rows.length; i++) {
    var row = [],
      cols = rows[i].querySelectorAll("td, th");

    for (var j = 0; j < cols.length; j++) {
      row.push(cols[j].innerText);
    }
    csv.push(row.join(","));
  }

  // Download CSV file
  downloadCSV(csv.join("\n"), filename);
}

<table>
  <tr>
    <th>Name</th>
    <th>Email</th>
    <th>Country</th>
  </tr>
  <tr>
    <td>John Doe</td>
    <td>john@gmail.com</td>
    <td>USA</td>
  </tr>
  <tr>
    <td>Stephen Thomas</td>
    <td>stephen@gmail.com</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Natly Oath</td>
    <td>natly@gmail.com</td>
    <td>France</td>
  </tr>
</table>
 <button onclick="exportTableToCSV('ps_file.csv')">
  Export HTML Table To CSV File
</button>