Keep retain filter state in sessionStorage. Closes VUFIND-1175.

themes/bootstrap3/js/common.js

@@ -361,4 +361,12 @@ $(document).ready(function commonDocReady() {
   });
   $('.facet.list-group .collapse').on('shown.bs.collapse', facetSessionStorage);
   $('.facet.list-group .collapse').on('hidden.bs.collapse', facetSessionStorage);
+
+  // retain filter sessionStorage
+  $('.searchFormKeepFilters').click(function() {
+    sessionStorage.setItem('vufind_retain_filters', this.checked);
+  });
+  if (sessionStorage.getItem('vufind_retain_filters')) {
+    $('.searchFormKeepFilters').prop('checked', sessionStorage.getItem('vufind_retain_filters') == 'true');
+  }
 });