diff --git a/app/templates/assiduites/pages/ajout_justificatif.j2 b/app/templates/assiduites/pages/ajout_justificatif.j2
index e1ee013e4..1194ff1a8 100644
--- a/app/templates/assiduites/pages/ajout_justificatif.j2
+++ b/app/templates/assiduites/pages/ajout_justificatif.j2
@@ -234,9 +234,11 @@
             const date_str_deb = document.getElementById("justi_date_debut").value
             const date_str_fin = document.getElementById("justi_date_debut").value
 
+
+
             return {
-                "deb": `${date_str_deb}T${assi_morning}`,
-                "fin": `${date_str_fin}T${assi_evening}`,
+                "deb": date_str_deb ? `${date_str_deb}T${assi_morning}` : "",
+                "fin": date_str_fin ? `${date_str_fin}T${assi_evening}` : "",
             }
         }