Magento display categories and sub-categories

<div class="block block-layered-nav">

    <div class="block-title">

        <strong><span><?php echo $this->__('Shop By Category') ?></span></strong>

    </div>

    <div class="block-content">

        <?php $productid = Mage::registry('current_product')->getId();

        $product = Mage::getSingleton('catalog/product')->load($productid);

        $parentIds = $product->getCategoryIds();

        $parentId = $parentIds[0];

        $_categories = Mage::getBlockSingleton('catalog/navigation');

        foreach ($_categories->getStoreCategories() as $_category) {

                $category = Mage::getModel('catalog/category');

                $category->load($_category->getId());

                $subcategories = explode(',', $category->getChildren());

                if(!in_array($_category->getId(),$parentIds)) { $hide="display:none"; $inactive="inactive"; } else { $hide=""; $inactive="active"; }

                ?>

                <div style="padding:5px 5px 0px 10px">

                        <div class="cat parent <?php echo $inactive;?>" style="font-size:15px"><?php echo $_category->getName() ?></div>

                        <div class="child" style="<?php echo $hide;?>">

                         <?php foreach ($subcategories as $subcategoryId) {

                                $category->load($subcategoryId);

                                if($category->getChildren() == '') {

                                        if(in_array($subcategoryId,$parentIds)) { $bold = "font-weight:bold"; } else { $bold = ""; }

                                      echo '<div class="subcat" style="'.$bold.'"><a href="' . $category->getURL() . '">' . $category->getName() . '</a></div>';

                                 } else {?>

                                <div class="subcat">

                                        <div class="parent active"><?php echo $category->getName() ?></div>

                                        <div class="child">

                                        <?php $subsubcategories = explode(',', $category->getChildren());

                                        foreach($subsubcategories as $subsubcatid) {

                                                if(in_array($subsubcatid, $parentIds)) { $bold = "font-weight:bold"; } else { $bold = ""; }

                                                $category->load($subsubcatid);

                                                echo '<div style="padding-left:10px;'.$bold.'"><a href="' . $category->getURL() . '">' . $category->getName() . '</a></div>';

                                        } ?>

                                        </div>

                                </div>

                        <?php }

                        }

                        ?>

                        </div>

                </div>

                <?php

        } ?>

    </div>

</div>

<script type="text/javascript">

    jQuery('.block-content .cat').click(function(){

        var t = jQuery(this);

        if(jQuery(this).next().css('display')=='none') {

                jQuery('.col-left .block-content .child').hide();

                t.next().show(); t.next().find('div.child').show("slow");

        } else {

                t.next().hide(); t.next().find('div.child').hide("slow");

        }

    });

</script>