How can i get selected checkbox value into database?

I have a checkbox with foreach data, I want to select 1 or maximum 5 row, and make the rest checkbox be uncheck and that uncheck checkbox can't be sumbitted into the database

This is the form

 <form action="/po_store" method="post">
                <div class="container">
                    <div class="row">
                        <div class="col-md-6">
                            @csrf
                            <div class="form-group">
                                <label>Tanggal PO</label>
                                <input class="form-control" type="text" name="tanggal_po" id="datepicker">
                                {!! $errors->first('tanggal_po','<span class="text-danger">:message</span>') !!}                                                                                        
                            </div>

                            <div class="form-group">
                                <label>No Po</label>
                                <input class="form-control" type="text" name="no_po">
                                {!! $errors->first('no_po','<span class="text-danger">:message</span>') !!}                                                            
                            </div>

                            <div class="form-group">
                                <label>Supplier</label>
                                <select name="supplier_nama" class="form-control">
                                    <option value=""hidden>Pilih Supplier</option>
                                    @foreach ($supplier as $s)
                                        <option value=""></option>
                                    @endforeach
                                </select>
                            </div>
                        </div>

                        <div class="col-md-6">
                            <div class="form-group">
                                <label>Apoteker</label>
                                <select name="apoteker_nama" class="form-control">
                                    <option value=""hidden>Pilih Apoteker</option>
                                    @foreach ($apoteker as $a)
                                        <option value=""></option>
                                    @endforeach
                                </select>
                            </div>

                            <div class="form-group">
                                <label>Keterangan</label>
                                <input class="form-control" type="text" name="keterangan">
                            </div>
                        </div>

                        <form action="" method="GET">
                            <div class="container-fluid" style="padding-top:25px">
                                <div class="row">
                                    <div class="col-md-11">
                                        <div class="form-group">
                                            <input type="text" name="cari" class="form-control" placeholder="Cari berdasarkan kode dan nama obat ...">
                                         </div>
                                        </div>
                                        <div class="form-group">
                                          <input type="submit" value="Cari" class="btn btn-primary">
                                    </div>
                            </div>
                        </form>

                        <table class="table table-bordered">
                            <tbody>
                                <tr class="text-center">
                                    <th>Pilih</th>
                                    <td>Kode Obat</td>
                                    <td>Nama Obat</td>
                                    <td>Harga Obat</td>
                                    <td>Jumlah Obat PO</td>
                                    <td>Total bayar</td>
                                </tr>
                                @foreach ($obat as $o)
                                <tr>
                                        <td>
                                            <input type="checkbox" name="select" value="">
                                        </td>
                                        <td>
                                            <input type="text" class="form-control" name="kode_obat" value="" readonly>
                                        </td>
                                        <td>
                                            <input type="text" class="form-control" name="nama_obat" value="" readonly>
                                        </td>
                                        <td>
                                            <input id="harga" type="text" class="form-control" name="harga_obat"  value="" onkeyup="sum()">
                                        </td>
                                        <td>
                                            <input id="jumlah" type="text" class="form-control" name="jumlah" onkeyup="sum()">
                                        </td>
                                        <td>
                                            <input id="total" type="text" class="form-control" name="total_harga" onkeyup="sum()" readonly>
                                        </td>
                                    </tr>
                                    @endforeach
                            </tbody>
                        </table>

                    </div>
                </div>
                  <button type="submit" class="btn btn-success simpan simp-po"><i class="fas fa-check"> Simpan</i></button>                
            </form>

This is the javascript to show calculate total field

function sum() {
            var harga = document.getElementById('harga').value;
            var jumlah = document.getElementById('jumlah').value;
            var hasil = parseInt(harga)*parseInt(jumlah);
            if(!isNaN(hasil)){
                document.getElementById('total').value = hasil;
            }
        }

I can't submit the form especially the checkbox because the total field can't be empty. But i want just the selected checkbox get the harga field and can be submit

This is how it's looks like