您需要添加 dom: 'B' 在 DataTable 初始化.

You need to add dom: 'B' at DataTable initialization.

片段:

$('#myTable').DataTable({
    dom: 'B',
    buttons: ['copy', 'csv', 'excel']
});

<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.4/jquery-ui.css" />
<link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/1.10.13/css/dataTables.jqueryui.css" />
<link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/buttons/1.2.4/css/buttons.jqueryui.css" />

<script type="text/javascript" src="https://code.jquery.com/jquery-2.2.4.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.4/jquery-ui.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jszip/2.5.0/jszip.js"></script>
<script type="text/javascript" src="https://cdn.rawgit.com/bpampuch/pdfmake/0.1.18/build/pdfmake.js"></script>
<script type="text/javascript" src="https://cdn.rawgit.com/bpampuch/pdfmake/0.1.18/build/vfs_fonts.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/1.10.13/js/jquery.dataTables.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/1.10.13/js/dataTables.jqueryui.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/buttons/1.2.4/js/dataTables.buttons.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/buttons/1.2.4/js/buttons.jqueryui.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/buttons/1.2.4/js/buttons.colVis.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/buttons/1.2.4/js/buttons.flash.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/buttons/1.2.4/js/buttons.html5.js"></script>
<script type="text/javascript" src="https://cdn.datatables.net/buttons/1.2.4/js/buttons.print.js"></script>


<table id="myTable">
    <thead>
    <tr>
        <th>Name</th>
        <th>Position</th>
        <th>Office</th>
        <th>Age</th>
        <th>Start date</th>
        <th>Salary</th>
    </tr>
    </thead>
    <tbody>
    <tr>
        <td>Tiger Nixon</td>
        <td>System Architect</td>
        <td>Edinburgh</td>
        <td>61</td>
        <td>2011/04/25</td>
        <td>$320,800</td>
    </tr>
    <tr>
        <td>Garrett Winters</td>
        <td>Accountant</td>
        <td>Tokyo</td>
        <td>63</td>
        <td>2011/07/25</td>
        <td>$170,750</td>
    </tr>
    <tr>
        <td>Ashton Cox</td>
        <td>Junior Technical Author</td>
        <td>San Francisco</td>
        <td>66</td>
        <td>2009/01/12</td>
        <td>$86,000</td>
    </tr>
    <tr>
        <td>Cedric Kelly</td>
        <td>Senior Javascript Developer</td>
        <td>Edinburgh</td>
        <td>22</td>
        <td>2012/03/29</td>
        <td>$433,060</td>
    </tr>
    <tr>
        <td>Airi Satou</td>
        <td>Accountant</td>
        <td>Tokyo</td>
        <td>33</td>
        <td>2008/11/28</td>
        <td>$162,700</td>
    </tr>
    <tr>
        <td>Brielle Williamson</td>
        <td>Integration Specialist</td>
        <td>New York</td>
        <td>61</td>
        <td>2012/12/02</td>
        <td>$372,000</td>
    </tr>
    <tr>
        <td>Herrod Chandler</td>
        <td>Sales Assistant</td>
        <td>San Francisco</td>
        <td>59</td>
        <td>2012/08/06</td>
        <td>$137,500</td>
    </tr>
    <tr>
        <td>Rhona Davidson</td>
        <td>Integration Specialist</td>
        <td>Tokyo</td>
        <td>55</td>
        <td>2010/10/14</td>
        <td>$327,900</td>
    </tr>
    <tr>
        <td>Colleen Hurst</td>
        <td>Javascript Developer</td>
        <td>San Francisco</td>
        <td>39</td>
        <td>2009/09/15</td>
        <td>$205,500</td>
    </tr>
    <tr>
        <td>Sonya Frost</td>
        <td>Software Engineer</td>
        <td>Edinburgh</td>
        <td>23</td>
        <td>2008/12/13</td>
        <td>$103,600</td>
    </tr>
    <tr>
        <td>Jena Gaines</td>
        <td>Office Manager</td>
        <td>London</td>
        <td>30</td>
        <td>2008/12/19</td>
        <td>$90,560</td>
    </tr>
    <tr>
        <td>Quinn Flynn</td>
        <td>Support Lead</td>
        <td>Edinburgh</td>
        <td>22</td>
        <td>2013/03/03</td>
        <td>$342,000</td>
    </tr>
    <tr>
        <td>Charde Marshall</td>
        <td>Regional Director</td>
        <td>San Francisco</td>
        <td>36</td>
        <td>2008/10/16</td>
        <td>$470,600</td>
    </tr>
    <tr>
        <td>Haley Kennedy</td>
        <td>Senior Marketing Designer</td>
        <td>London</td>
        <td>43</td>
        <td>2012/12/18</td>
        <td>$313,500</td>
    </tr>
    <tr>
        <td>Tatyana Fitzpatrick</td>
        <td>Regional Director</td>
        <td>London</td>
        <td>19</td>
        <td>2010/03/17</td>
        <td>$385,750</td>
    </tr>
    <tr>
        <td>Michael Silva</td>
        <td>Marketing Designer</td>
        <td>London</td>
        <td>66</td>
        <td>2012/11/27</td>
        <td>$198,500</td>
    </tr>
    <tr>
        <td>Paul Byrd</td>
        <td>Chief Financial Officer (CFO)</td>
        <td>New York</td>
        <td>64</td>
        <td>2010/06/09</td>
        <td>$725,000</td>
    </tr>
    <tr>
        <td>Gloria Little</td>
        <td>Systems Administrator</td>
        <td>New York</td>
        <td>59</td>
        <td>2009/04/10</td>
        <td>$237,500</td>
    </tr>
    <tr>
        <td>Bradley Greer</td>
        <td>Software Engineer</td>
        <td>London</td>
        <td>41</td>
        <td>2012/10/13</td>
        <td>$132,000</td>
    </tr>
    <tr>
        <td>Dai Rios</td>
        <td>Personnel Lead</td>
        <td>Edinburgh</td>
        <td>35</td>
        <td>2012/09/26</td>
        <td>$217,500</td>
    </tr>
    <tr>
        <td>Jenette Caldwell</td>
        <td>Development Lead</td>
        <td>New York</td>
        <td>30</td>
        <td>2011/09/03</td>
        <td>$345,000</td>
    </tr>
    <tr>
        <td>Yuri Berry</td>
        <td>Chief Marketing Officer (CMO)</td>
        <td>New York</td>
        <td>40</td>
        <td>2009/06/25</td>
        <td>$675,000</td>
    </tr>
    <tr>
        <td>Caesar Vance</td>
        <td>Pre-Sales Support</td>
        <td>New York</td>
        <td>21</td>
        <td>2011/12/12</td>
        <td>$106,450</td>
    </tr>
    <tr>
        <td>Doris Wilder</td>
        <td>Sales Assistant</td>
        <td>Sidney</td>
        <td>23</td>
        <td>2010/09/20</td>
        <td>$85,600</td>
    </tr>
</table>