Look at the jsFiddle.
I used jQuery for what you need.
<table>
<tr>
<td colspan="6" class="linha_space"></td>
</tr>
<tr>
<td colspan="3">Dummy1</td>
<td colspan="3">Dummy2</td>
</tr>
<tr>
<td colspan="2"><input name="aperf_cursos[]" type="text" /></td>
<td colspan="2"><input name="aperf_entidades[]" type="text" /></td>
<td colspan="2"><a href="#" class="adicionar">Add</a><a href="#" class="remover" style="display: none;">Delete</a></td>
</tr>
<tr>
<td colspan="6" class="linha_space"></td>
</tr>
</table>
$(function() {
$(document).on('click', '.adicionar', function(event){
var o = $(event.target);
var tr = o.closest('table');
tr.after(tr.clone());
tr.find('.adicionar').remove();
tr.find('.remover').show();
tr.next().find('input, select').val('');
tr.next().find('.remover').hide();
});
$(document).on('click', '.remover', function(event){
var o = $(event.target);
var table = $(o.closest('table'));
table.remove();
});
});