diff --git a/js/build_page.js b/js/build_page.js
index 7aa08da..3b2745f 100644
--- a/js/build_page.js
+++ b/js/build_page.js
@@ -113,6 +113,11 @@
     var duplicateSubjectBoolNext, duplicateSubjectBoolPrev;
     var duplicateSubjectCounter = 0;
     
+    // Flush existing classes
+    document.querySelectorAll('.message').forEach(function(classe) {
+        classe.classList.add('is-hidden');
+    });
+    
     for (var [i, classe] of classes.entries()) {        
         var hora_inici = formatDate(new Date(parseInt(classe.begins)*1000));
         var hora_final = formatDate(new Date(parseInt(classe.ends)*1000));