Solution 1 :

You can add like this:
Use insertAfter() function to insert after search box.

$(document).ready(function() {   
  var table = $('#example').DataTable({ 
        select: false,
        dom: '<"testdiv">frtip',
        "columnDefs": [{
            className: "Name", 
            "targets":[0],
            "visible": false,
            "searchable":false
        }]
    });//End of create main table

    $("div.testdiv").html('<div style="float: left"> left content </div> <div style="float: right"> right content </div>').insertAfter( ".dataTables_filter" );
    
    $('#example tbody').on( 'click', 'tr', function () {
   
    alert(table.row( this ).data()[0]);

} );
});
body {
  margin: 2rem;
}
.paginate_button {
  border-radius: 0 !important;
}
.dataTables_wrapper .dataTables_filter {
  width: 100%;
}
.testdiv {
  background: #f0f0f0;
  padding: 10px;
  float: left;
  width: 100%;
}
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-table/1.9.0/bootstrap-table.min.css">
<link rel="stylesheet" href="https://cdn.datatables.net/1.10.9/css/jquery.dataTables.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<script src="https://cdn.datatables.net/1.10.9/js/jquery.dataTables.min.js"></script>
<table id="example" class="display" cellspacing="0" 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>

    <tfoot>
        <tr>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Age</th>
            <th>Start date</th>
            <th>Salary</th>
        </tr>
    </tfoot>

    <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>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>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>
        <tr>
            <td>Angelica Ramos</td>
            <td>Chief Executive Officer (CEO)</td>
            <td>London</td>
            <td>47</td>
            <td>2009/10/09</td>
            <td>$1,200,000</td>
        </tr>
        <tr>
            <td>Gavin Joyce</td>
            <td>Developer</td>
            <td>Edinburgh</td>
            <td>42</td>
            <td>2010/12/22</td>
            <td>$92,575</td>
        </tr>
        <tr>
            <td>Jennifer Chang</td>
            <td>Regional Director</td>
            <td>Singapore</td>
            <td>28</td>
            <td>2010/11/14</td>
            <td>$357,650</td>
        </tr>
        <tr>
            <td>Brenden Wagner</td>
            <td>Software Engineer</td>
            <td>San Francisco</td>
            <td>28</td>
            <td>2011/06/07</td>
            <td>$206,850</td>
        </tr>
        <tr>
            <td>Fiona Green</td>
            <td>Chief Operating Officer (COO)</td>
            <td>San Francisco</td>
            <td>48</td>
            <td>2010/03/11</td>
            <td>$850,000</td>
        </tr>
        <tr>
            <td>Shou Itou</td>
            <td>Regional Marketing</td>
            <td>Tokyo</td>
            <td>20</td>
            <td>2011/08/14</td>
            <td>$163,000</td>
        </tr>
        <tr>
            <td>Michelle House</td>
            <td>Integration Specialist</td>
            <td>Sidney</td>
            <td>37</td>
            <td>2011/06/02</td>
            <td>$95,400</td>
        </tr>
        <tr>
            <td>Suki Burks</td>
            <td>Developer</td>
            <td>London</td>
            <td>53</td>
            <td>2009/10/22</td>
            <td>$114,500</td>
        </tr>
        <tr>
            <td>Prescott Bartlett</td>
            <td>Technical Author</td>
            <td>London</td>
            <td>27</td>
            <td>2011/05/07</td>
            <td>$145,000</td>
        </tr> 
    </tbody>
</table>

Solution 2 :

Add this css in your css file

.testdiv {
    width: 100%;
    float: left;
    padding: 5px 0;
}

https://codepen.io/venkatramanank/pen/ZEYrqRb

Problem :

I want to have a div below the the search box line of the datatable with one sub div float left and another fload right as follows:
<div style="float: left"> left content </div> <div style="float: right"> right content </div>

My approach for it was from this link: https://datatables.net/examples/advanced_init/dom_toolbar.html

$(document).ready(function() {
    $('#example').DataTable( {
        "dom": 'fr<"testdiv">tip'
    } );
    $("div.testdiv").html('<div style="float: left"> left content </div> <div style="float: right"> right content </div>');
} );

Here i have problem that is the div which i wished have is appearing in same line as the search box. How can i make it appear in next line?

Comments

Comment posted by rakesh kotian

I want it to appear in next line of search box, but with your answer it appears in the same line as the searchbox.

Comment posted by venkatramanan

Now you can check

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