WordPressのキーワード・タクソノミー(セレクト・チェックボックス)の複合検索メモ

<form method="get" action="<?php echo esc_url(home_url('/'));?>" name="worksearch">
<input type="text" name="s" id="s" value="<?php echo get_search_query(); ?>" placeholder="キーワード">
<?php
//カスタム投稿タイプの一覧を取得
$args = array(
'public' => true,
'_builtin' => false
);
$post_types = get_post_types( $args );
?>

<!--
<?php if(count($post_types) != 0):?>
<select name="post_type">
<?php foreach ( $post_types as $post_type ) : ?>
<option value="<?php echo $post_type; ?>"><?php echo esc_html( get_post_type_object( $post_type )->label ); ?></option>
<?php endforeach;?>
</select>
<?php endif; ?>
-->

<select name="post_type" style="display: none;">
<option value="work" selected>求人情報</option>
</select>

<?php
$selected = get_query_var("work_area",0);
$args = array(
'show_option_all' => '勤務地を選ぶ',
'taxonomy' => 'work_area',
'name' => 'work_area',
'value_field' => 'slug',
'hide_empty' => false,
'hierarchical'=> true,
'selected' => $selected
);
wp_dropdown_categories($args);
?>

<?php
$selected = get_query_var("work_occupation",0);
$args = array(
'show_option_all' => '職種を選ぶ',
'taxonomy' => 'work_occupation',
'name' => 'work_occupation',
'value_field' => 'slug',
'hide_empty' => false,
'selected' => $selected
);
wp_dropdown_categories($args);
?>

<?php
$selected = get_query_var("work_status",0);
$args = array(
'show_option_all' => '雇用形態を選ぶ',
'taxonomy' => 'work_status',
'name' => 'work_status',
'value_field' => 'slug',
'hide_empty' => false,
'selected' => $selected
);
wp_dropdown_categories($args);
?>

<?php
/*
$selected = get_query_var("work_commitment",0);
$args = array(
'descendants_and_self' => 0,
'selected_cats' => false,
'popular_cats' => false,
'walker' => null,
'taxonomy' => 'work_commitment',
'checked_ontop' => true
);
wp_terms_checklist($args);
*/
?>

<ul>
<?php
$terms = get_terms('work_commitment','hide_empty=0');
foreach ( $terms as $term ) :
?>
<li>
<label>
<input type="checkbox" name="work_commitment" value="<?php echo $term->slug; ?>" id="<?php echo $term->term_id;; ?>"><?php echo $term->name; ?>
</label>
</li>
<?php endforeach; ?>
</ul>

<input type="submit" value="検索">
</form>