Here is a little WordPress tip / trick. For anyone who is trying to build their sidebar and or want to add a dropwdown list style for category listing, this is one simple method.
http://codex.wordpress.org/Template_Tags/wp_dropdown_categories
You can use the code snip they’ve provided
<li id=”categories”>lt;h2><?php _e(’Posts by Category’); ?></h2>
<?php wp_dropdown_categories(’show_option_none=Select category’); ?>
<script type=”text/javascript”><!–
var dropdown = document.getElementById(”cat”);
function onCatChange() {
if [...]