是否按主行展开/折叠行分组?

var groupColumn = 2;
var table = $('#example').DataTable({
    "columnDefs": [{
        "visible": false,
        "targets": groupColumn
    }],
    "order": [
        [groupColumn, 'asc']
    ],
    "displayLength": 25,
    "drawCallback": function(settings) {
        var api = this.api();
        var rows = api.rows({
            page: 'current'
        }).nodes();

        console.log(typeof rows);

        //debugger;

        /*      rows.forEach(function(node) {
         console.log("rows =" + node);
         }); */



        var last = null;

        api.column(groupColumn, {
            page: 'current'
        }).data().each(function(group, i) {

            if (last !== group) {
                $(rows).eq(i).before(
                        '<tr class="group"><td colspan="5">' + group + '</td></tr>'
                );

                last = group;
            }
        });
    }
});

// Order by the grouping
$('#example tbody').on('click', function({target}) {
    if (target.parentNode.className !== 'group') return;
    //console.log($(this).find('[role=row]'))
    $(target.parentNode).nextUntil(':not([role=row])').slideToggle()

});

tr.group,
tr.group:hover {
    background-color: #ddd !important;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.datatables.net/1.10.19/js/jquery.dataTables.min.js"></script>
<link rel="stylesheet" href="https://cdn.datatables.net/1.10.19/css/jquery.dataTables.min.css">

<table id="example" class="display" style="width:100%">
    <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>
    </tbody>
</table>