собственно сам обработчик:
$('#question_type_1 .add_answer').on('click', function (e) {
let trs = $('#question_type_1 [class^=answer_number_]:last-child').attr('class');
trs = trs.replace('answer_number_','');
//console.log(trs);
trs *= 1; trs += 1;
$('#question_type_1 tbody').append(
'<tr class="answer_number_' + trs + '">'+
'<td>' + trs +'</td>'+
'<td>'+
' <input class="form-control" type="text" name="answer' + trs + '">'+
'</td>'+
'<td>'+
' <span class="badge badge-secondary">True</span>'+
' <span class="badge badge-danger active">False</span>'+
' <span class="badge badge-success add_answer pl-2 pr-2">+</span>'+
' <span class="badge badge-danger del_answer pl-2 pr-2">-</span>'+
'</td>'+
'</tr>'
);
return false;
});
и сам html
<tbody>
<tr class="answer_number_1">
<td>1</td>
<td>
<input class="form-control" type="text" name="answer1">
</td>
<td>
<span class="badge badge-secondary">True</span>
<span class="badge badge-danger active">False</span>
<span class="badge badge-success add_answer pl-2 pr-2">+</span>
<span class="badge badge-danger del_answer pl-2 pr-2">-</span>
</td>
</tr>
</tbody>
что нужно сделать, в обработчике или в html, чтобы вновь добавленный элемент tr, реагировал на существующий обработчик?