Do you want to create a search form with dropdown to search all categories? While there’s probably a plugin for this, we have created a quick code snippet that you can use to add dropdown to search by all categories or define a specific category in WordPress.
Instructions:
All you have to do is add this code to your theme’s index.php file or where you want to display the search form:
<form role="search" method="get" id="searchform" action="<?php bloginfo('siteurl'); ?>">
<div>
<label class="screen-reader-text" for="s">Search for:</label>
<input type="text" value="" name="s" id="s" />
in <?php wp_dropdown_categories( 'show_option_all=All Categories' ); ?>
<input type="submit" id="searchsubmit" value="Search" />
</div>
</form>
Note: If this is your first time adding code snippets in WordPress, then please refer to our guide on how to properly add code snippets in WordPress, so you don’t accidentally break your site.
If you liked this code snippet, please consider checking out our other articles on the site like: 12 best WordPress plugins for bloggers and how to save partial form data in WordPress.
Thanks! I spend weeks for this solution. I just put this code creating a file searchform.php on my child theme
Not working with custom post typewith custom taxonomy
How would you do it with a custom post type?
where would i add this code as this is exactly what im after
Looks like you need to add it on a HTML widget.