diff --git a/app/templates/but/parcour_formation.j2 b/app/templates/but/parcour_formation.j2
index 92de363da22a3414754d91e0eeddf98a9e3dd78b..c2e5e1b88f0b6d2318b2a1e589b92d43010367fe 100644
--- a/app/templates/but/parcour_formation.j2
+++ b/app/templates/but/parcour_formation.j2
@@ -161,7 +161,8 @@ Choisissez un parcours...
 function ue_assoc_niveau(event, niveau_id) {
     let ue_id = event.target.value;
     let url = "";
-    let force = document.getElementById('force_modification').checked;
+    let checkbox = document.getElementById('force_modification');
+    let force = checkbox ? checkbox.checked : false;
     if (ue_id == "") {
         /* Dé-associe */
         ue_id = event.target.dataset.ue_id;