Hide Attributes from frontend which values are not given from backend in Magento

<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Academic Free License (AFL 3.0)
 * that is bundled with this package in the file LICENSE_AFL.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/afl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    design
 * @package     base_default
 * @copyright   Copyright (c) 2010 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/afl-3.0.php  Academic Free License (AFL 3.0)
 */

/**
 * Product additional attributes template
 *
 * @see Mage_Catalog_Block_Product_View_Attributes
 */
?>
<?php
    $_helper = $this->helper('catalog/output');
    $_product = $this->getProduct()
?>
<?php if($_additional = $this->getAdditionalData()): ?>
    <h2><?php echo $this->__('Additional Information') ?></h2>
    <table class="data-table" id="product-attribute-specs-table">
        <col width="25%" />
        <col />
        <tbody>
        <!--<?php foreach ($_additional as $_data): ?>
            <tr>
                <th class="label"><?php echo $this->htmlEscape($this->__($_data['label'])) ?></th>
                <td class="data"><?php echo $_helper->productAttribute($_product, $_data['value'], $_data['code']) ?></td>
            </tr>
        <?php endforeach; ?>-->
            <?php foreach ($_additional as $_data): ?>
            <?php $_attribute = $_product->getResource()->getAttribute($_data['code']);
if (!is_null($_product->getData($_attribute->getAttributeCode())) && ((string)$_attribute->getFrontend()->getValue($_product) != '')) { ?>
            <tr>
                <th class="label">
                    <?php echo $this->htmlEscape($this->__($_data['label'])) ?>
                </th>
                <td class="data">
                    <?php echo $_helper->productAttribute($_product, $_data['value'], $_data['code']) ?>
                </td>
            </tr>
            <?php } ?>
            <?php endforeach; ?>

        </tbody>
    </table>
    <script type="text/javascript">decorateTable('product-attribute-specs-table')</script>
<?php endif;?>