diff --git a/include/top.php b/include/top.php
index da5cd5da9..6cf5eb920 100755
--- a/include/top.php
+++ b/include/top.php
@@ -109,14 +109,15 @@ if (Auth::check()) {
         'details' => tr('Dettagli'),
         'loading' => tr('Caricamento'),
         'waiting' => tr('Impossibile procedere'),
-        'waitingMessage' => tr('Prima di proseguire devi selezionare alcuni elementi!'),
+        'waitingMessage' => tr('Prima di proseguire devi selezionare alcuni elementi.'),
         'hooksExecuting' => tr('Hooks in esecuzione'),
         'hookExecuting' => tr('Hook "_NAME_" in esecuzione'),
         'hookMultiple' => tr('Hai _NUM_ notifiche'),
         'hookSingle' => tr('Hai 1 notifica'),
         'hookNone' => tr('Nessuna notifica'),
-        'singleCalendar' => tr("E' presente un solo periodo!"),
+        'singleCalendar' => tr("E' presente un solo periodo."),
         'noResults' => tr('Nessun elemento trovato'),
+        'signatureMissing' => tr('Firma mancante.'),
     ];
     foreach ($translations as $key => $value) {
         echo '
diff --git a/modules/interventi/modals/anteprima_firma.php b/modules/interventi/modals/anteprima_firma.php
index 0e3df6251..7b31d8511 100644
--- a/modules/interventi/modals/anteprima_firma.php
+++ b/modules/interventi/modals/anteprima_firma.php
@@ -120,7 +120,9 @@ if (get('anteprima') !== null) {
 
         saveButton.addEventListener("click", function (event) {
             if (signaturePad.isEmpty()) {
-                alert("Please provide signature first.");
+                alert(globals.translations.signatureMissing);
+                event.preventDefault();
+                return;
             } else {
                 image_data = signaturePad.toDataURL("image/jpeg", 100);
                 $('#firma_base64').val(image_data);