从新输入字段添加值，然后与现有数据库值相加

Question

i want to add stock, then it will sum with the database stock the field for the total sum(jumlahtotal) didn't work

anyway, i already put js at the header template

<div class="content-wrapper">
    <div class="panel-body">
        <form action="" method="POST">
            <?php echo validation_errors(); ?>
            <input type="hidden" name="id" value="<?= $buku['id'];?>">
      <input type="hidden" name="judul" value="<?= $buku['judul'];?>">
      <input type="hidden" name="pengarang" value="<?= $buku['pengarang'];?>">
      <input type="hidden" name="penerbit" value="<?= $buku['penerbit'];?>">
      <input type="hidden" name="tahun_terbit" value="<?= $buku['tahun_terbit'];?>">
      <input type="hidden" name="isbn" value="<?= $buku['isbn'];?>">
      <input type="hidden" name="rak" value="<?= $buku['rak'];?>">
      <input type="hidden" name="tgl_input" value="<?= $buku['tgl_input'];?>">
      <div class="form-group">
        <label for="jumlah">Jumlah Masuk</label>
        <input type="number" class="form-control" id="masuk" name="jumlah" value="0">
          <?= form_error('masuk','<small class="text-danger">','</small>') ?>
      </div>

            <div class="form-group">
                <label>Jumlah Total</label>
                <input type="number" class="form-control" id="jumlah" name="jumlah" value="<?= $buku['jumlah_buku']?>" readonly>
                    <?= form_error('jumlah','<small class="text-danger">','</small>') ?>
            </div>

            <div class="form-group">
                <input type="number" id="jumlahtotal">
            </div>
                <button type="submit" name="ubah" class="btn btn-primary">Update Data</button>
        </form>
    </div>
</div>

  <script>
    $(document).ready(function() {
        $('input').change(function () {
            var total = 0;
            $('input[name=jumlah]').each(function(){
                total = total+parseInt($(this).val());
            })
            $('input[id=jumlahtotal]').html(total);
        })
    })
</script>

i already checked the js is running

Answer 1

You are trying to set the innerHTML of an input tag in your code

$('input[id=jumlahtotal]').html(total);

In HTML, input tag is an unpaired tag. It means you don't put anything inside <input> and </input>. It's just <input>. What you are trying is to put <input> someValue </input> but via jquery.

I think you want to do this instead

$('input[id=jumlahtotal]').val(total);

This just sets the value attribute of the input element. And it's the correct way to set the value to an input element.