Test Case Boilerplate
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HTML
<table>
<thead>
<tr><td>header</td></tr>
</thead>
<tbody class="className">
</tbody>
</table>
JavaScript
$('.className:visible').append('<tr><td>content</td></tr>');
<table>
<thead>
<tr><td>header</td></tr>
</thead>
<tbody class="className">
</tbody>
</table>
$('.className:visible').append('<tr><td>content</td></tr>');