magento show subcategories from categories in static block

For showing Subcategory please put this follow those steps 

 

<?php

 /**

 * ** Instructions for Use **

 *

 * 1. Upload this page to your installation at:

 *     /app/design/frontend/[INTERFACE]/[THEME]/template/catalog/navigation/custom-category.phtml

 *

 * 2. Enter the following code in a static block:

 *   {{block type="catalog/navigation" name="catalog.navigation" template="catalog/navigation/custom-category.phtml"}}

 *

 * 3. Select the static block as the content source for the categories you require

 *

 * 4. Create new CSS styles as required

 *

 **/

?>

 

<?php $_categories=$this->getCurrentChildCategories() ?>

 

<?php if($_categories->count()): ?>

<ul class="category-links"> 

 <?php foreach ($_categories as $_category): ?>

        <?php if($_category->getIsActive()): ?>

        <li class="<?php echo $this->htmlEscape($_category->getUrlKey()) ?>">

           <a href="<?php echo $this->getCategoryUrl($_category) ?>">

              <?php echo $this->htmlEscape($_category->getName()) ?>

           </a>

        </li>

        <?php endif; ?>

    <?php endforeach ?>

</ul>

<? endif; ?>