diff --git a/app/templates/assiduites/pages/ajout_justificatif.j2 b/app/templates/assiduites/pages/ajout_justificatif.j2
index 28c4b6159a..c4885b3f8e 100644
--- a/app/templates/assiduites/pages/ajout_justificatif.j2
+++ b/app/templates/assiduites/pages/ajout_justificatif.j2
@@ -219,20 +219,27 @@
     }
 
     function dayOnly() {
+        const { deb, fin } = getDates();
 
         if (document.getElementById('justi_journee').checked) {
             document.getElementById("justi_date_debut").type = "date"
+            document.getElementById("justi_date_debut").value = deb.slice(0, deb.indexOf('T'))
+
             document.getElementById("justi_date_fin").type = "date"
+            document.getElementById("justi_date_fin").value = fin.slice(0, fin.indexOf('T'))
         } else {
             document.getElementById("justi_date_debut").type = "datetime-local"
+            document.getElementById("justi_date_debut").value = `${deb}T${assi_morning}`
+
             document.getElementById("justi_date_fin").type = "datetime-local"
+            document.getElementById("justi_date_fin").value = `${fin}T${assi_evening}`
         }
     }
 
     function getDates() {
         if (document.querySelector('.page #justi_journee').checked) {
             const date_str_deb = document.querySelector(".page #justi_date_debut").value
-            const date_str_fin = document.querySelector(".page #justi_date_debut").value
+            const date_str_fin = document.querySelector(".page #justi_date_fin").value