controller :
	public function GetSearchMaxOrg_ByPaket()
	{
	if(!empty($_POST["selectpaket"])) {
	$result = $this->m_utama->getQuery("SELECT * FROM tb_paket_order INNER JOIN tb_harga_paket_order ON tb_harga_paket_order.id_name_paket = tb_paket_order.id WHERE tb_paket_order.nama_paket='".$_POST['selectpaket']."'")->result();
	if (count($result) > 0) {
		echo '<option value="#N/A">Pilih Jumlah Orang</option>';
		foreach($result as $loop_data):
      	echo '<option value="'.$loop_data->id.'">'.$loop_data->max_user.'</option>';
      endforeach;
  		} else {
  			echo '<option value="">Pilih Jumlah Orang</option>';
  		}
	}
	else {
		echo '<option value="">Pilih Jumlah Orang</option>';
	}
}

js :
function getState(val)
{
    $.ajax({
    type: "POST",
    url: "<?php echo site_url('Admin/GetSearchMaxOrg_ByPaket')?>",
    data:'selectpaket='+val,
    success: function(data){
        $("#selectjmlorg").html(data);

    }
    });
}

view :

 <!-- The Modal -->
 <div class="modal fade" id="smallmodal" tabindex="-1" role="dialog" aria-labelledby="smallmodalLabel" aria-hidden="true">
                <div class="modal-dialog modal-xl" role="document">
                    <div class="modal-content">
                        <div class="modal-header">
                            <h5 class="modal-title" id="smallmodalLabel">Create Order</h5>
                            <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                                <span aria-hidden="true">&times;</span>
                            </button>
                        </div>
                        <div class="modal-body">

                            <form action="<?php echo base_url('Admin/btn_create_order')?>" method="post">
                                <div class="form-group">
                                    <div class="row">

                                    <div class="col-lg-6">
                                    <label>Username</label>
                                    <input class="au-input au-input--full" type="text" name="username" id="username"placeholder="username">
                                </div>

                                <div class="col-lg-6">
                                    <label>No HP</label>
                                    <input class="au-input au-input--full" type="text" name="nohp" placeholder="No Handphone">
                                </div>

                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="selectSm" class=" form-control-label">Pilih Paket</label>
                                    <select name="selectpaket" id="selectpaket" class="form-control-sm form-control" onchange="getState(this.value);">
                                    <option value="">Pilih Paket</option>
                                    <?php foreach($data_paket as $loop_data):?>
                                    <option value="<?php echo $loop_data->nama_paket   ;?>"><?php echo $loop_data->nama_paket;?></option>
                                 <?php endforeach; ?>
                                    </select>
                                </div>

                                 <div class="form-group">
                                    <label for="selectSm" class=" form-control-label">Pilih Jumlah Orang</label>
                                    <select name="selectjmlorg" id="selectjmlorg" class="form-control-sm form-control" onchange="getVal();">
                                    <option value="">Pilih Jumlah Orang</option>
                                    </select>
                                </div>
                                 <div class="form-group">
                                    <label>Total Harga</label>
                                    <input class="au-input au-input--full" type="number" name="sumprice">
                                </div>
                              <div class="form-group">
                                    <label>Masukan Jumlah Orang</label>
                                    <input class="au-input au-input--full" type="number" name="m_org" placeholder="Masukan Jumlah Orang">
                                </div>
                            <div class="form-group">
                                    <label>Masukan Jumlah Uang</label>
                                    <input class="au-input au-input--full" type="number" name="m_uang" placeholder="Masukan Jumlah Uang">
                            </div>
                        <div class="form-group">
                            <label for="selectSm" class=" form-control-label">Pilih Status</label>
                            <select name="selectstatus" class="form-control-sm form-control">
                            <option value="0">Pilih Status</option>
                            </select>
                        </div>


                        <div class="modal-footer">
                            <button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>
                            <button type="submit" class="btn btn-primary">Confirm</button>
                        </div>
                        </form>
                    </div>
                </div>
            </div>

              <!-- end modal -->