Datatables - adding data attributes to javascrpt data

HTML

<script src="http://datatables.net/download/build/nightly/jquery.dataTables.js?_=11"></script>
<link rel="stylesheet" href="http://cdn.datatables.net/1.10.2/css/jquery.dataTables.css">
<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 data-search="snoop">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>
               ...

JavaScript

$(document).ready(function() {
    $('#example').DataTable({
        "columnDefs": [{
                "targets": 2,
                // Not sure why this doesn't work properly
                "createdCell": function (td, cellData, rowData, row, col) {
                    if ( cellData == "Tokyo" ) {
                        $(td).attr("data-search","snoop");
                    }
                }
            }]
    });
} );