<textarea class="hw_widopt_desc" name="<?php 
echo $this->get_field_name('hw_widopt_desc');
?>
" id="<?php 
echo $this->get_field_id('hw_widopt_desc');
?>
"></textarea>
</p>
    <input type="hidden" class="hw_widopt_setting" name="<?php 
echo $this->get_field_name('hw_widopt_setting');
?>
" id="<?php 
echo $this->get_field_id('hw_widopt_setting');
?>
" value="<?php 
echo AWC_WidgetFeature_saveconfig::encode_config($saveconfig);
?>
"/>
<p>
    <input type="button" class="button" name="saveconfig_btn" value="<?php 
_e('Lưu');
?>
" onclick="hwawc_widfea_saveconfig(this,'#<?php 
echo $this->get_field_id('result');
?>
')"/>
    <div id="<?php 
echo $this->get_field_id('result');
?>
"></div>
</p>
 /**
  * ajax callback
  */
 public function _ajax_hwawc_widfea_saveconfig()
 {
     if (!wp_verify_nonce($_REQUEST['nonce'], "hwawc_widfea_saveconfig_nonce")) {
         exit("No naughty business please");
     }
     if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
         //$result = json_encode($result);
         $setting = isset($_POST['setting']) ? $_POST['setting'] : '';
         if (!empty($setting)) {
             //remove setting from this widget feature
             $setting = AWC_WidgetFeature_saveconfig::decode_config($setting);
             $setting = $this->remove_settings($setting);
             //encode widget settings
             $setting = AWC_WidgetFeature_saveconfig::encode_config($setting);
         }
         $data = array('name' => isset($_POST['name']) ? $_POST['name'] : '', '_group' => isset($_POST['group']) ? $_POST['group'] : '', 'setting' => $setting, 'description' => isset($_POST['description']) ? $_POST['description'] : '', 'widget' => isset($_POST['widget']) ? $_POST['widget'] : '');
         $insert_id = $this->add_widget_setting($data);
         echo $insert_id;
         //return new id inserted to database
     } else {
         header("Location: " . $_SERVER["HTTP_REFERER"]);
     }
     die;
 }