multiple countdown timer js

<?php
  $id_user = $this->session->userdata('id_user');
?>
<div class="container">
    <h4><?php echo $judul;?></h4>
</div>
<div class="container panel panel-default">
    <div class="panel-body">
        <?php
        if($this->session->flashdata('psn_success') <> '') {
        ?>
            <div class="alert alert-dismissible alert-success">
              <button type="button" class="close" data-dismiss="alert">&times;</button>
              <strong><span class="glyphicon glyphicon-ok"></span> <?php echo $this->session->flashdata('psn_success');?></strong>
            </div>
        <?php
        }
        if($this->session->flashdata('psn_gagal') <> '') {
        ?>
            <div class="alert alert-dismissible alert-danger">
              <button type="button" class="close" data-dismiss="alert">&times;</button>
              <strong>&times; <?php echo $this->session->flashdata('psn_gagal');?></strong>
            </div>
        <?php
        }
        ?>
        <table class='table table-striped table-hover display' id='example'>
            <thead style="text-align:center">
                <tr>
                    <th>No.</th>
                    <th>Kode Pesanan</th>
                    <th>Nama Pembeli</th>
                    <th>Jumlah Pesanan</th>
                    <th>Total Harga</th>
                    <th>Deadline Lunas</th>
                    <th>Status</th>
                    <th>Opsi</th>
                </tr>
            </thead>
            <tbody>
            <script>
            var timerData = [];
            function countdown(id_pembeli) {
                var seconds = timerData[id_pembeli].remaining;
                var hour = Math.floor(seconds/(60*60))%24;
                var min = Math.floor(seconds/60) % 60;
                var sec = seconds % 60;
                if (sec < 10) {
                    sec = "0" + sec;
                }
                document.getElementById('waktu'+id_pembeli).innerHTML = hour+":"+min+":"+sec;
                if (seconds <= 0) {
                    clearInterval(timerData[id_pembeli].timerId);
                    document.getElementById('waktu' + id_pembeli).innerHTML = "DEADLINE!";
                } else {
                    seconds--;
                }
                timerData[id_pembeli].remaining = seconds;
            }

            function timer(id_pembeli, seconds) {
                timerData[id_pembeli] = {
                    remaining: seconds,
                    timerId: setInterval(function () { countdown(id_pembeli); }, 1000)
                };
            }
            </script>
            <?php
                $no = 1;
                $countpembeli = $this->M_reseller->getpembeliwuser($id_user)->num_rows();
                if($countpembeli == 0){
                    /*
                     $this->session->set_flashdata(
                          "psn_success",
                          "<div class=\"alert alert-danger\" id=\"alert\">
                           <i class=\"glyphicon glyphicon-ok\"></i> Data Kosong !
                           <button type=\"button\" class=\"close\" data-dismiss=\"alert\">&times;</button> </div>");
                     redirect('reseller/entry_data');
                    */
                } else {
                    $getpembeli = $this->M_reseller->getpembeliwuser($id_user)->result();
                    foreach($getpembeli as $gp) {
                        $id_pembeli = $gp->id_pembeli;
                        $getmaster  = $this->M_reseller->getmasterwpemuser($id_pembeli, $id_user)->result();
                        $getjml  = $this->M_reseller->getdetailwpembeli($id_pembeli)->num_rows();
                        //Ambil/SUM total harga
                        $total = $this->db->query("
                            SELECT id_t_sales_master, sum(total_harga) as total
                            FROM t_reseller_sales_detail
                            WHERE id_t_sales_master = '$id_pembeli' ")->result();
                        $total_harga = 'Rp.&nbsp;'.number_format($total[0]->total,2,".",",");
                        //DEADLINE LUNASAN
                        $sla = strtotime($getmaster[0]->waktu_deadline);
                        $now = time();
                        $seconds = $sla - $now;
                        if($seconds<= 0) {
                            $waktu_deadline = 'Waktu Habis';
                            $update = $this->db->query("
                                UPDATE t_reseller_sales_master
                                SET status='canceled'
                                WHERE id_t_sales_master='$id_pembeli' ");
                        } else {
                            $waktu_deadline =  '<div style="font-size:40px;margin-top:7px;" id="waktu'.$id_pembeli.'" >
                                                DEADLINE!</div>';
                        }
                        ?>
                    <tr>
                        <td><?php echo $no++;?>.</td>
                        <td><?php echo $getmaster[0]->id_t_sales_master;?></td>
                        <td><?php echo $gp->nama;?></td>
                        <td><?php echo $getjml; ?></td>
                        <td><?php echo $total_harga; ?></td>
                        <td><?php echo $waktu_deadline; ?></td>
                        <td><?php echo $getmaster[0]->status;?></td>
                        <td>
                        <button class="btn btn-warning btn-xs" data-toggle="modal"
                                data-target="#data_sales_master_edit<?php echo $gp->id_pembeli; ?>" >
                        <span class="glyphicon glyphicon-pencil"></span> Edit</button>
                        <a href="<?php echo base_url('reseller/data_sales_detail/'.$id_pembeli);?>"
                           class="btn btn-success btn-xs" >
                        <span class="glyphicon glyphicon-plus"></span> Olah Sapi</a>
                        <a href="<?php echo base_url('reseller/data_sales_master_hapus/'.$id_pembeli);?>"
                           class="btn btn-danger btn-xs" onclick="return confirm('Hapus data?')">&times; Hapus</a></td>
                    </tr>
                     <script type="text/javascript">
                         timer(<?php echo "{$id_pembeli},{$seconds}";?>);
                     </script>
                    <?php
                        include('data_sales_bukti_bayar.php');
                        include('data_sales_master_edit.php');
                    }
                }
                ?>
            </tbody>
        </table>
    </div>
</div>