diff --git a/themes/bootstrap3/js/facets.js b/themes/bootstrap3/js/facets.js
index 949b1d75949ad7dfd28a34f6afd45cd6a90b5d37..d9629e488ccb930ff8af0858807a6f399b4bffd5 100644
--- a/themes/bootstrap3/js/facets.js
+++ b/themes/bootstrap3/js/facets.js
@@ -142,7 +142,7 @@ VuFind.register('lightbox_facets', function LightboxFacets() {
           button.before(list);
           if (list.length && htmlDiv.find('.js-facet-next-page').length) {
             button.attr('data-page', page + 1);
-            button.attr('href', button.attr('href').replace(/facetpage=\d+/, 'facetpage='+(page+1)));
+            button.attr('href', button.attr('href').replace(/facetpage=\d+/, 'facetpage=' + (page + 1)));
             button.text(VuFind.translate('more') + ' ...');
             button.removeAttr('disabled');
           } else {