要删除旧的TableB，可以尝试source.outerHTML = "";
然后删除对象：delete(source);个
关于在tableA中插入TableB，我不明白。您想像<tableA><tableB></tableB></tableA>一样插入，还是只移动TableB的<td>？

因为您已经为副本应用了一个新的id，所以可以使用它来访问克隆的元素。

function copytable() {
  var source = document.getElementById('TableB');
  var destination = document.getElementById('TableA');
  var copy = source.cloneNode(true);
  copy.setAttribute('id', 'tableA');
  destination.parentNode.replaceChild(copy, destination);
}

function deletCopy() {
  var el = document.getElementById('tableA');
  el.innerHTML = '';
}

个字符
但是访问新表中的元素的问题是，由于克隆的内部元素有id，所以有多个元素具有相同的id。如果可以使用class而不是id作为td元素，则

function copytable() {
  var source = document.getElementById('TableB');
  var destination = document.getElementById('TableA');
  var copy = source.cloneNode(true);
  copy.setAttribute('id', 'TableA');
  destination.parentNode.replaceChild(copy, destination);
}

function deletCopy() {
  var el = document.getElementById('TableA');
  el.innerHTML = '';
}

function changeCopy(){
  var el = document.getElementById('TableA');
  el.querySelector('.col1').innerHTML = 'Column A';
  el.querySelector('.col2').innerHTML = 'Column B';
  el.querySelector('.col3').innerHTML = 'Column C';
}

<button onclick="copytable()">Copy Table</button>
<button onclick="deletCopy()">Delete Table</button>
<button onclick="changeCopy()">Update Table</button>

<br />
<br />

<table id="TableA">
  <!--<tbody></tbody>-->
</table>
<br />

<table id="TableB" style="border:solid">
  <thead>
    <tr>
      <td class="col1">Column 1</td>
      <td class="col2">Column 2</td>
      <td class="col3">Column 3</td>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Data a</td>
      <td>Data b</td>
      <td>Data c</td>
    </tr>
  </tbody>
</table>
<br />

的字符串

要删除源表，可以执行以下操作：

var tableB = document.getElementById('TableB');
tableB.parentNode.removeChild(tableB);

字符串
您可以在复制后立即更改复制的表，例如：

function copytable() {
  var source = document.getElementById('TableB');
  var destination = document.getElementById('TableA');
  var copy = source.cloneNode(true);
  copy.id = 'TableA';

  /* you can change what you want already here, e.g: */
  [].forEach.call(copy.querySelectorAll('td'), function(item, index) {
    switch (item.textContent.trim()) {
      case 'Column 1':
        item.textContent = 'Column A';
        break;
      case 'Column 2':
        item.textContent = 'Column B';
        break;
      case 'Column 3':
        item.textContent = 'Column C';
        break;
    }
  });

  destination.parentNode.replaceChild(copy, destination);
}

function deleteTableB() {
  var tableB = document.getElementById('TableB');
  tableB.parentNode.removeChild(tableB);
}

<button onclick="copytable()">Copy Table</button>
<button onclick="deleteTableB()">Delete TableB</button>

<br />
<br />

<table id="TableA">
  
</table>
<br />

<table id="TableB" style="border:solid">
  <thead>
    <tr>
      <td id="col1">Column 1</td>
      <td id="col2">Column 2</td>
      <td id="col3">Column 3</td>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Data a</td>
      <td>Data b</td>
      <td>Data c</td>
    </tr>
  </tbody>
</table>
<br />

的数据