Question

With the code blow I retrieve the current parent category and his children. Is it possible to add an active class for the current child?

<?php
$currentCat = Mage::registry('current_category');
if ( $currentCat->getParentId() == Mage::app()->getStore()->getRootCategoryId() )
    {
    $loadCategory = $currentCat;
    }
    else
    {
    $loadCategory = Mage::getModel('catalog/category')->load($currentCat->getParentId());
    }
    $subCategories = explode(',', $loadCategory->getChildren());
    foreach ( $subCategories as $subCategoryId )
    {
    $cat = Mage::getModel('catalog/category')->load($subCategoryId);
    if($cat->getIsActive())
        {
        echo '<li><a href="'.$cat->getURL().'">'.$cat->getName().'</a></li>';
        }
     }
?>

Answer 1

You already have the current category, so you can check it’s ID against the IDs of the categories being looped through.

Where you have

echo '<li><a href="'.$cat->getURL().'">'.$cat->getName().'</a></li>';

Change it to do the check for the ID and then add the “active” class when found

$class = '';
if ($currentCat->getId() == $cat->getId())
{
    $class = ' class="active"';
}
echo '<li'.$class.'><a href="'.$cat->getURL().'">'.$cat->getName().'</a></li>';