add value from new input field then sum with existing database value - php

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.