diff --git a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-detail.tt b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-detail.tt
index 1f0d336a73..56559c5ffd 100644
--- a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-detail.tt
+++ b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-detail.tt
@@ -56,7 +56,7 @@
     <div class="container-fluid">
         <div class="row">
             <div class="col-lg-9">
-                <div id="catalogue_detail_biblio" class="maincontent">
+                <div id="catalogue_detail_biblio" class="maincontent" data-biblionumber="[% biblio.biblionumber %]">
 
                     <div id="bookcover">
                         [% IF ( biblio.title ) %]