// Script for getting posts
function ajax_filter_get_posts( $taxonomy, $type ) {

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

  $taxonomy = $_POST['taxonomy'];
  $type = $_POST['type']; // Post type

  // WP Query
  $args = array(
    'tag' => $taxonomy,
    'post_type' => $type, // Post type
    'posts_per_page' => 10,
  );

  // If taxonomy is not set, remove key from array and get all posts
  if( !$taxonomy ) {
    unset( $args['tag'] );
  }

  $query = new WP_Query( $args );

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

    <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
    <?php the_excerpt(); ?>

  <?php endwhile; ?>
  <?php else: ?>
    <h2>No posts found</h2>
  <?php endif;

  die();
}

add_action('wp_ajax_filter_posts', 'ajax_filter_get_posts');
add_action('wp_ajax_nopriv_filter_posts', 'ajax_filter_get_posts');