Update elements inside a for using jquery

Thanks for the help,

  <tbody>
                  <?php  foreach($itens as $key=>$item): ?>
                    <tr>
                      <td>
                        <?=  $item->item_id ?>
                      </td>
                      <td>
                        <?= $item->getNomeProduto($item->item_prod) ?>
                      </td>
                      <td>
                        <?php  if($pedMagazine->maga_tolerancia==1){?>
                          <input type="number" name="item_vlruni" id="item_vlruni<?= $key ?>" value="<?= $item->item_vlruni?>" disabled/>
                          <input type="hidden" name="item_vlruni[]" value="<?= $item->item_vlruni?>" />
                          <?php }else echo  $item->item_vlruni  ;?>
                      </td>
                      <td>
                        <?php  if($pedMagazine->maga_tolerancia==1){?>
                          <input type="number" name="item_qtd" id="item_qtd<?= $key ?>" min="<?= round($item->item_qtd*(1-($pedMagazine->maga_toleranciaperc/100)))?>" max="<?= round($item->item_qtd*(1+($pedMagazine->maga_toleranciaperc/100)))?>" onchange='sePedidoItem.somar(<?= $key ?>);' step="1"
                          value="<?= $item->item_qtd?>" />
                          <input type="hidden" name="item_id[]" value="<?= $item->item_qtd?>" />
                          <?php }else {echo $item->item_qtd; }?>
                      </td>
                      <td>
                        <?php  if($pedMagazine->maga_tolerancia==1){?>
                          <input type="number" name="item_vlrtot[]" id="item_vlrtot<?= $key ?>" value="<?= $item->item_vlrtot?>" disabled/>
                          <input type="hidden" name="item_vlrtot[]" value="<?= $item->item_vlrtot?>" />
                          <?php }else echo $item->item_vlrtot; ?>
                      </td>
                      <?php $subTotal+=$item->item_vlrtd ;?>
                    </tr>
                    <?php  endforeach;  ?>
                </tbody>

And in jquery it was like this

 somar: function (i) {

// soma para os itens editados no pedido
$('#vlrTot').val($('#qtd').val() * $('#vlrUni').val())

// logica para atualizar campos na tela confirmar 
var antigo = $('#item_vlrtot' + i).val()
// atualiza o campo vlrtot
$('#item_vlrtot' + i).val($('#item_qtd' + i).val() * $('#item_vlruni' + i).val())
var soma = $('#item_vlrtot' + i).val() - antigo
soma = soma + parseInt(document.getElementById('subTotal').textContent)
// atualiza valortotal
document.getElementById('subTotal').textContent = soma  },

Ciro, I see that you have a table with inputs for unit value, quantity and total value.

The first problem I see is the repetition of id s in the elements. as% s of% s should be unique, consider changing the strategy used to name them, or even remove% with% (in the case above it seems to me that this should not affect your application).

Another point, I do not see the need for a id and id simultaneously. I believe input[type='hidden'] is only interesting if input[type='number'] , or rather, use input[type='hidden'] for everything and just put maga_tolerancia == 1 on inputs.

Finally, add a input[type='number'] to the line, we can do this to use the line ( readonly='readonly' ) as scope for your operations, as well as classes for class s.

<tbody>
  <?php $i =0; foreach($itens as $item): ?>
  <tr class="item">
    <td>
      <?=  $item->item_id ?>
    </td>
    <td>
      <?= $item->getNomeProduto($item->item_prod) ?>
    </td>
    <td>
      <input type="number" name="item_vlruni[]" class="item_vlruni" 
            value="<?= $item->item_vlruni?>" <?php if($pedMagazine->maga_tolerancia!=1){?>readonly='readonly' disabled='disabled'<?php }?>/>
    </td>
    <td>      
      <input type="number" name="item_qtd[]" class="item_qtd" step="1" 
            min="<?= round($item->item_qtd*(1-($pedMagazine->maga_toleranciaperc/100)))?>" 
            max="<?= round($item->item_qtd*(1+($pedMagazine->maga_toleranciaperc/100)))?>" 
            value="<?= $item->item_qtd?>" <?php if($pedMagazine->maga_tolerancia!=1){?>readonly='readonly' disabled='disabled'<?php }?> />
    </td>
    <td>
      <input type="number" name="item_vlrtot[]" class="item_vlrtot" 
            value="<?= $item->item_vlrtot?>" <?php if($pedMagazine->maga_tolerancia!=1){?>readonly='readonly' disabled='disabled'<?php }?>/>
    </td>
    <?php //$subTotal+=$item->item_vlrtot ;?>
  </tr>
  <?php $i++; endforeach;  ?>
</tbody>

Note that I am not a programmer tr , so there may be some basic error in the above suggestion.

Now let's go to input :

var itens = $('.item');
itens.each(function (indice) {
  var item = $(this);
  var item_vlruni = $(".item_vlruni", item);
  var item_qtd = $(".item_qtd", item);
  var item_vlrtot = $(".item_vlrtot", item);

  var onInput = function (event) {
    var vlruni = parseFloat(item_vlruni.val());
    var qtd = parseFloat(item_qtd.val());
    item_vlrtot.val(vlruni * qtd);
  }

  item_vlruni.on("input", onInput);
  item_qtd.on("input", onInput);  
});

Note that I added PHP to JavaScript , I made it so that it was possible to select all the rows, then I go through each row selecting only the inputs inside them, so I pass the row as the second argument in the selector , as in the example class='item' , finally I make the tr of the event $(".item_vlruni", item) , which is where the calculation will be performed.