为什么验证错误消息不显示

Question

我正要更新sql中的现有数据。 我正在使用带有验证错误的Ajax更新数据

ajax验证可用于我的帐户创建和更改密码

下面是我的Ajax代码

$('#form-battery-update').submit(function(e) {
e.preventDefault();
var me = $(this);

// perform ajax
$.ajax({
// url: me.attr('action'),
url: '<?php echo base_url(); ?>msasset/update_battery_form_validation',
type: 'post',
data: me.serialize(),
dataType: 'json',
success: function(response) {
if (response.success == true) {
  // if success we would show message
  // and also remove the error class
  $('#the-message').append('<div class="alert alert-success">' +
    '<span class="glyphicon glyphicon-ok"></span>' +
    ' UPS Battery has been created' +
    '</div>');
  $('.form-group').removeClass('has-error')
          .removeClass('has-success');
  $('.text-danger').remove();

  // reset the form
  me[0].reset();

  // close the message after seconds
  $('.alert-success').delay(500).show(10, function() {
    $(this).delay(3000).hide(10, function() {
      $(this).remove();

    });
  })
}

else {
  $.each(response.messages, function(key, value) {
    var element = $('#' + key);

    element.closest('div.form-group')
    .removeClass('has-error')
    .addClass(value.length > 0 ? 'has-error' : 'has-success')
    .find('.text-danger')
    .remove();
    element.after(value);
  });
}
}
});
});

下面是我的视图文件夹中的代码

<div class="card-body p-0">

        <?php echo form_open("msasset/update_battery_form_validation", array("id" => "form-battery-update", "class" => "form-horizontal")) ?>


        <div class="row">
          <div class="col-lg-5 d-none d-lg-block bg-register-image"></div>
          <div class="col-lg-7">
            <div class="p-5">
              <div class="text-center">

                <h1 class="h4 text-gray-900 mb-4"><?php echo $title; ?></h1>
                  <div id="the-message"></div>
              </div>
              <?php
           if(isset($fetch_single_battery))
           {
                foreach($fetch_single_battery->result() as $row)
                {
           ?>
           <div class="form-group">
                <label>Battery SerialNumber</label> </br>
                <p class="form-control"> <?php  echo $row->SerialNumber; ?></p>

           </div>
           <div class="form-group">
                <label>PO Number</label> </br>
                <input type="text" name="PONumber" value="<?php echo $row->PONumber; ?>" class="form-control"/>
           </div>
           <div class="form-group">
           </div>
           <div class="form-group">
                <label>Ticket</label>
                <input type="text" name="ticketid" value="<?php echo $row->TicketNumber; ?>" class="form-control" />
                <span class="text-danger"><?php echo form_error("ticketid"); ?></span>
           </div>
           <div class="form-group">
           </div>
           <div class="form-group">
                <label>Data Port</label>
                <select class="form-control" name="select_port">
                    <option class="form-control" selected><?php echo $row->DataPort; ?></option>
                  <?php foreach ($GetPortLocation as $Port) { ?>
                    <option value="<?php echo $Port['DataPort']; ?>"><?php echo $Port['DataPort']; ?></option>
                <?php   } ?>
                </select>
                <span class="text-danger"><?php echo form_error("select_port"); ?></span>
                      <span class="text-danger"></span>
           </div>
           <div class="form-group">
                <label>UPS Asset Tag</label>
                <input type="text" name="ups_asset_tag" value="<?php echo $row->UPS_AssetTag; ?>" class="form-control" />
                <span class="text-danger"></span>

           </div>
           <div class="form-group">
                <label>Date Installed</label>
                <input type="date" name="date_installed" value="<?php echo $row->DateInstalled; ?>"  class="form-control" />
                <span class="text-danger"></span>
           </div>

           <div class="form-group">
                <label>Status</label>
                <select class="form-control" name="select_status">
                <option class="form-control" selected><?php echo $row->Status; ?></option>
                <?php foreach($get_AssetStatus as $AssetStatus){?>
                  <option value="<?php echo $AssetStatus['AssetStatus']; ?>"><?php echo $AssetStatus['AssetStatus']; ?></option>
                  <?php }  ?>
                </select>

           </div>
           <div class="form-group">
                <input type="hidden" name="hidden_id" value="<?php echo $row->ID; ?>" />
                <input type="submit" name="update" id="update" value="Update" class="btn btn-info" />
                    <input type="submit" name="insert" id="insert" value="Update" class="btn btn-primary">
           </div>
           <?php
                }
           }

           ?>
          </form>
            </div>
          </div>
        </div>
      </div>

低于我的控制器的代码

function update_battery_form_validation()
    {
        $data = array('success' => false, 'messages' => array());

        $this->load->library('form_validation');
        $this->form_validation->set_rules('PONumber','po number','required');
        // $this->form_validation->set_rules('ticketid','ticket id','required');



        if($this->form_validation->run() == TRUE)
        {

            $this->load->model('assets_model');
            $data  = array(
                'PONumber' => $this->input->post('PONumber'),
                'TicketNumber' => $this->input->post('ticketid'),
                'DataPort' => $this->input->post('select_port'),
                'UPS_AssetTag' => $this->input->post('ups_asset_tag'),
                'DateInstalled' => $this->input->post('date_installed'),
                'Status' => $this->input->post('select_status'),
                'PerformedBy' => $this->session->userdata('user_name')
            );
            if($this->input->post('update'))
            {
                $this->assets_model->update_battery($data,$this->input->post('hidden_id'));
                $this->session->set_flashdata('batteries_updated','New battery has been updated successfully');
                redirect('msasset/ups_batteries');
            }
        }
        else
        {
          // echo  validation_errors();
          foreach ($_POST as $key => $value)
          {
            $data['messages'][$key] = form_error($key);
          }

        }
                echo json_encode($data);
    }

我期望每当有一个空字段时，都应该给我一个该字段必填的消息，并且如果所有字段都填充了数据，它也不会加载页面或保存数据