我使用了以下代码，但当我从下拉列表中选择类别时，没有显示任何内容，页面如下https://eakdigital.com/blog/

模板文件

<div id="ajax-cases">
<?php
// WP Query
$args = array(
\'post_type\' => \'post\',
\'post_status\' => \'publish\',
\'nopaging\' => true, // show all posts in one go
);
$query = new WP_Query( $args );
$tax = \'category\';
$terms = get_terms( $tax, $args);
$count = count( $terms );
if ( $count > 0 ): ?>
<div class="post-tags">
<?php
echo \'<select>\';
foreach ( $terms as $term ) {
$term_link = get_term_link( $term, $tax ); 
echo \'<option value="\' . $term_link . \'" class="tax-filter" title="\'.$term->slug.\'">\' . $term->name . \'</option> \';
}
echo \'</select>\';
</div>
<?php endif; 
?></div>
<div class="tagged-posts">
//result must display here
</div>

jQuery(document).ready(function(jQuery) {
jQuery(\'.post-tags select\').on(\'change\', function(event) {


// Prevent default action - opening tag page
if (event.preventDefault) {
    event.preventDefault();
} else {
    event.returnValue = false;
}

// Get tag slug from title attirbute
var selecetd_taxonomy = jQuery(this).find(\'option:selected\').attr("title");

// After user click on tag, fade out list of posts
jQuery(\'.tagged-posts\').fadeOut();

data = {
    action: \'filter_posts\', // function to execute
    afp_nonce: afp_vars.afp_nonce, // wp_nonce
    taxonomy: selecetd_taxonomy, // selected tag
    };

jQuery.post( afp_vars.afp_ajax_url, data, function(response) {

    if( response ) {
    alert(response);
        // Display posts on page
        jQuery(\'.tagged-posts\').html( response );
        // Restore div visibility
        jQuery(\'.tagged-posts\').fadeIn();
    };
});
});
});

function ajax_filter_posts_scripts() {
// Enqueue script
wp_register_script(\'afp_script\', get_template_directory_uri() . \'/js/ajax-filter-posts.js\', false, null, false);
wp_enqueue_script(\'afp_script\');

wp_localize_script( \'afp_script\', \'afp_vars\', array(
\'afp_nonce\' => wp_create_nonce( \'afp_nonce\' ), // Create nonce which we later will use to verify AJAX request
\'afp_ajax_url\' => admin_url( \'admin-ajax.php\' ),
)
);
}
add_action(\'wp_enqueue_scripts\', \'ajax_filter_posts_scripts\', 100);
function ajax_filter_get_posts( $taxonomy ) {

// Verify nonce
if( !isset( $_POST[\'afp_nonce\'] ) || !wp_verify_nonce( $_POST[\'afp_nonce\'], \'afp_nonce\' ) )
die(\'Permission denied\');

$taxonomy = $_POST[\'taxonomy\'];

// WP Query
$args = array(

\'post_type\' => \'post\',
\'nopaging\' => true, // show all posts in one go
);
echo $taxonomy;
// If taxonomy is not set, remove key from array and get all posts
if( !$taxonomy ) {
unset( $args[\'tag\'] );
}else{
// This is the code which you are missing. You need to add taxonomy query if taxonomy is set.
$arg[\'tax_query\']= array(
array(
\'taxonomy\' => \'category\',
\'field\' => \'slug\',
\'terms\' => array( $taxonomy ),
\'include_children\' => true, // set true if you want post of its child     category also
\'operator\' => \'IN\'
),
);
}

$query = new WP_Query( $args );

if ( $query->have_posts() ) : while ( $query->have_posts() ) : $query->the_post();

$output  = \'<h2><a href="\'.get_permalink().\'">\'. get_the_title().\'</a></h2>\';
$output .= get_the_excerpt();

$result = \'success\';

endwhile; else:
$output = \'<h2>No posts found</h2>\';
$result = \'fail\';
endif;

$response = json_encode($output);
echo $response;
die();
}