Repeater
原文：https://www.advancedcustomfields.com/resources/repeater/
//循环
if( have_rows('preview') ):
// Loop through rows.
while( have_rows('preview') ) : the_row();
// Load sub field value.
$bookname1 = get_sub_field('bookname1');
$bookpdf = get_sub_field('bookpdf');
echo '<div class="mulu">';
echo '<div class="mulu-name">';
echo get_the_title($bookname1);
echo '</div>';
echo '<div class="mulu-pdf">';
echo '<a href="'.$bookpdf.'">目錄預覽</a>';
echo '</div>';
echo '</div>';
// Do something...
// End loop.
endwhile;
// No value.
else :
endif;
