Redirect to Post List by Taxonomy on User Selection of Taxonomy Dropdown?

Question

(Moderator's note: The original title was "drop down taxonomy")

I want to add a drop-down box filled with my custom taxonomies, so when someone selects any value, it redirects to corresponding page. I tried out this code, which worked

<?php wp_dropdown_categories( array( 'taxonomy' => 'name of taxonomy' ) ); ?>

The problem is I want a the page to redirect without the user needing to press any buttons. How can I do this?

this question was resolved but i want to modify further, i want to add a shortcode, so that i can also call drop-down-list into my post, i tried this but not working add_shortcode('drop','the_taxonomy_dropdown');

but when i call this in my post [drop="location"] its not working, whats the problem?

Answer 1

Hi @ntechi:

Here's a function I wrote which I named the_taxonomy_dropdown() to give you what I think you are looking for.

function the_taxonomy_dropdown($taxonomy) {
  $id = "{$taxonomy}-dropdown";
  $js =<<<SCRIPT
<script type="text/javascript">
 jQuery(document).ready(function($){
  $("select#{$id}").change(function(){
    window.location.href = $(this).val();
  });
 });
</script>
SCRIPT;
  echo $js;
  $terms = get_terms($taxonomy);
  echo "<select name=\"{$id}\" id=\"{$id}\">";
  foreach($terms as $term) {
    echo '<option value="';
    echo get_term_link(intval($term->term_id),$taxonomy);
    echo '">' . "{$term->name}</option>";
  }
  echo "</select>";
}

You can put the_taxonomy_dropdown() in your theme's functions.php file and call it from one of your theme's template files like so:

<?php the_taxonomy_dropdown('name of taxonomy'); ?>

Notice I didn't use wp_dropdown_categories() because it sets the <option>'s values to term_id instead of the term's permalink. You need the permalink in order to set the window.location.href on the client end. Had we used wp_dropdown_categories() it have would added more complexity; it would have required issuing an HTTP GET request with term_id to a page on the server that would then redirect to the term's permalink. But it's much easier to just build the HTML <select> ourselves as I did (and it's more peformant, since it doesn't take an extra HTTP request.)

Of course, be sure to remember wp_enqueue_script() jQuery in an 'init' hook, also in your theme's functions.php file:

add_action('init','jquery_init');
function jquery_init() {
  wp_enqueue_script('jquery');
}

Answer 2

I was looking at this problem again today, that is, the dropdown element returned by wp_dropdown_categories() setting option values to the term's ID..

Now whilst this makes the dropdown a little useless for filter dropdowns or jump menus, it is actually possible to rejiggle the JS used so it works "as is"...

Here's a basic example, which is based on the code posted above.

function the_taxonomy_dropdown( $taxonomy = '', $query_var = '' ) {

    if( empty( $taxonomy ) )
        return;

    if( empty( $query_var ) )
        $query_var = $taxonomy;

    $select_id = "{$taxonomy}-dropdown";
    $url_base = get_bloginfo('url') . "/$query_var/";
    ?>

    <script type="text/javascript">
    jQuery(document).ready(function($){
        $("select#<?php echo $select_id; ?>").change(function(){
            var term = this.options[this.selectedIndex].text;
            window.location.href = "<?php echo $url_base; ?>" + term;
        });
    });
    </script>

    <?php
    wp_dropdown_categories( array( 'taxonomy' => $taxonomy, 'id' => $select_id ) );
}

NOTE: This examples JS assumes you are using pretty permalinks.

If your taxonomy uses a query var that differs to the taxonomy slug you pass into the function, simply add the query var as the second parameter..

the_taxonomy_dropdown( 'post_tag', 'tag' );

Please note, this is just an example to show you how to work around the issue with wp_dropdown_categories and custom taxonomies by making changes to the JS.

Also for reference, there's a ticket here that was due for a patch. http://core.trac.wordpress.org/ticket/13258