js 动态rowspan

<table id="myTable" border="1">
  <tr>
    <td>Group A</td>
    <td>Item 1</td>
  </tr>
  <tr>
    <td></td>
    <td>Item 2</td>
  </tr>
  <tr>
    <td>Group B</td>
    <td>Item 3</td>
  </tr>
</table>

function setRowSpan() {
  const table = document.getElementById('myTable');
  let currentGroup = null;
  let rowspan = 1;

  for (let i = 0; i < table.rows.length; i++) {
    const row = table.rows[i];
    const groupCell = row.cells[0];

    if (groupCell.textContent) {
      if (currentGroup === groupCell.textContent) {
        rowspan++;
        groupCell.rowSpan = rowspan;
        groupCell.style.display = 'none'; // Hide the duplicate cell
      } else {
        currentGroup = groupCell.textContent;
        rowspan = 1;
      }
    }
  }
}

setRowSpan();