Expandable parent terms with child terms as links taxonomy menu

This Drupal snippet prints 1 vocabulary's parent terms as expandable menus and the child terms as links to SEO friendly url's.

Parent term 1 (expandable)
- child term 1 (link)
- child term 1 (link)
Parent term 2 (expandable)
- child term 3 (link)

Our thanks to www.computerminds.co.uk for the modifications to this.

Print into a block or where ever you would like the category list/menu to appear.

Snippet:
<?php
// accordion taxonomy menu
// by Chris Herberte
// ** don't forget to change $vocabulary
//
$vocabulary = 1;
//drupal_add_js('misc/collapse.js');
$lastdepth = 1;
$topoflist = 1;
$nid = 0;
if (arg(0) == 'node' && is_numeric(arg(1)) && ! arg(2)) {
    $nid = arg(1);
    $terms = taxonomy_node_get_terms($nid);
    rsort($terms);
    $tid = $terms[0]->tid;
} elseif (arg(0) == 'taxonomy' && arg(1) == 'term') {
    $terms = preg_split('/[+ ,]/', arg(2));
    $tid = $terms[0];
}
$parents = taxonomy_get_parents($tid);
foreach ($parents as $parent) {
    $i++;
}
$tree = taxonomy_get_tree($vocabulary);

foreach ($tree as $key => $term) {
    if ( $term->depth == 0 ) {
        $title = $term->name;
        if ($topoflist == 0) {
            print '</ul></li></ul>'."\n";
        }
        if ($tree[$key+1]->depth==1){
            if ($term->tid == $parent->tid) {
                print '<ul>'."\n".
                '<li class="title active" onClick="showHide(event)">'.$title.
                "\n".'<ul class="active">'."\n";
            } else {
                print '<ul>'."\n".
                '<li class="title" onClick="showHide(event)">'.$title.
                "\n".'<ul class="menu">'."\n";
            }
        }
        else {
            print '<ul>'."\n".
                '<li class="title">'.l($title,'taxonomy/term/'.$term->tid).
                "\n".'<ul class="menu">'."\n";
        }
        $topoflist = 0;
    }
    if ($term->depth > 0) {
        if ($term->tid == $tid) {
            print '<li id="darker">' . l($term->name, "taxonomy/term/$term->tid") . '</li>' . "\n";
        } else {
            print '<li class="leaf notdarker">' . l($term->name, "taxonomy/term/$term->tid") . '</li>' . "\n";
        }
    }
    $lastdepth = $term->depth;
}
print '</ul></li></ul>';
?>