js遍历tr怎样合并tr

<table id="myTable">
  <tr><td>1</td><td>A</td></tr>
  <tr><td>2</td><td>A</td></tr>
  <tr><td>3</td><td>B</td></tr>
  <tr><td>4</td><td>B</td></tr>
  <tr><td>5</td><td>B</td></tr>
</table>

<script>
function mergeRows() {
  const table = document.getElementById('myTable');
  let rowspan = 1;
  let prevText = '';

  for (let i = 0; i < table.rows.length; i++) {
    const cellText = table.rows[i].cells[1].innerText; // 假设根据第二列的内容合并

    if (cellText === prevText) {
      rowspan++;
      table.rows[i - rowspan + 1].cells[1].rowSpan = rowspan;
      table.rows[i].cells[1].style.display = 'none'; // 隐藏被合并的单元格
    } else {
      rowspan = 1;
      prevText = cellText;
    }
  }
}

mergeRows();
</script>