I have a table which have a tbody and x number of rows containing persons and their ages like this..
<tbody>
<tr>
<td class="number">4</td>
<td class="name">Name</td>
<td class="age" data-date="2004-11-22 00:00:00">13</td>
</tr>
<tr>
<td class="number">5</td>
<td class="name">Name</td>
<td class="age" data-date="2003-11-22 00:00:00">14</td>
</tr>
$('.age').each(function(i, e) {
var now = new Date();
var date = new Date(e.dataset.date);
$(this).html(now.getFullYear() - date.getFullYear());
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table>
<tbody>
<tr>
<td class="number">4</td>
<td class="name">Name</td>
<td class="age" data-date="2004-11-22 00:00:00"></td>
</tr>
<tr>
<td class="number">5</td>
<td class="name">Name</td>
<td class="age" data-date="2003-11-22 00:00:00"></td>
</tr>
</tbody>
</table>