现在如何在我的php代码中显示空字段

How to not show my code between li/li together with li/li on website when my field in form is empty?

Exactly every li disappears when is empty in admin panel.

<?php if (class_exists('MultiPostThumbnails')) : ?>
    <?php $imgID = get_post_thumbnail_id(); $url = MultiPostThumbnails::get_post_thumbnail_url(get_post_type(), '10-image');?>

        <li>
         <a href="<?php echo $url; ?>" alt="<?php the_title(); ?>" data-lightbox="my-gallery">
           <?php    MultiPostThumbnails::the_post_thumbnail(get_post_type(), '10-image'); ?>
           </a>
      </li>

<?php endif; ?>

U have to use IF around ur LI

<?php if (class_exists('MultiPostThumbnails')) : ?>
    <?php $imgID = get_post_thumbnail_id(); $url = MultiPostThumbnails::get_post_thumbnail_url(get_post_type(), '10-image');?>
    <?php if($url): ?>
            <li>
             <a href="<?php echo $url; ?>" alt="<?php the_title(); ?>" data-lightbox="my-gallery">
               <?php    MultiPostThumbnails::the_post_thumbnail(get_post_type(), '10-image'); ?>
               </a>
          </li>
    <?php endif; ?>
<?php endif; ?>