Custom taxonomy dropdown walker

app.js

$(".goToCategory").change( function() {
    if ( this.options[this.selectedIndex].value !== 0 ) {
        location.href = this.options[this.selectedIndex].getAttribute('data-permalink');
    }
});

functions.php

/**
 * Create HTML dropdown list of Categories.
 *
 * @package WordPress
 * @since 2.1.0
 * @uses Walker
 */
class Walker_TaxonomyDropdown extends Walker_CategoryDropdown {
    /**
     * @see Walker::$tree_type
     * @since 2.1.0
     * @var string
     */
    var $tree_type = 'category';

    /**
     * @see Walker::$db_fields
     * @since 2.1.0
     * @todo Decouple this
     * @var array
     */
    var $db_fields = array ('parent' => 'parent', 'id' => 'term_id');

    /**
     * Start the element output.
     *
     * @see Walker::start_el()
     * @since 2.1.0
     *
     * @param string $output   Passed by reference. Used to append additional content.
     * @param object $category Category data object.
     * @param int    $depth    Depth of category. Used for padding.
     * @param array  $args     Uses 'selected' and 'show_count' keys, if they exist. @see wp_dropdown_categories()
     */
    function start_el( &$output, $category, $depth = 0, $args = array(), $id = 0 ) {
        $pad = str_repeat(' ', $depth * 3);

        /** This filter is documented in wp-includes/category-template.php */
        $cat_name = apply_filters( 'list_cats', $category->name, $category );
        $cat_permalink = get_term_link( $category );

        $output .= "\t<option data-permalink=\"".$cat_permalink."\" class=\"level-$depth\" value=\"".$category->name."\"";
        if ( $category->term_id == $args['selected'] )
            $output .= ' selected="selected"';
        $output .= '>';
        $output .= $pad.$cat_name;
        if ( $args['show_count'] )
            $output .= '&nbsp;&nbsp;('. number_format_i18n( $category->count ) .')';
        $output .= "</option>\n";
    }
}

index.php

<?php wp_dropdown_categories( array(
    'taxonomy' => 'ciudad',
    'hide_empty' => false,
    'hierarchical' => 1,
    'show_option_all' => __('SELECCIONA TU GUÍA', 'theme'),
    'walker' => new Walker_TaxonomyDropdown,
    'class' => 'goToCategory',
    'orderby' => 'name'
    ));
?>