diff --git a/app/static/js/assiduites.js b/app/static/js/assiduites.js
index d077ee0c25..ecc2ce5166 100644
--- a/app/static/js/assiduites.js
+++ b/app/static/js/assiduites.js
@@ -573,20 +573,43 @@ function formatDate(date, styles = { dateStyle: "full" }) {
 function updateDate() {
   const dateInput = document.querySelector("#tl_date");
 
-  const date = dateInput.valueAsDate;
+  const date = dateInput.valueAsDate ?? new Date();
+  let dateStr = "";
 
   if (!verifyNonWorkDays(date.getDay(), nonWorkDays)) {
-    $("#datestr").text(formatDate(date).capitalize());
-    dateInput.setAttribute("value", date.toISOString().split("T")[0]);
-    return true;
+    dateStr = formatDate(date).capitalize();
   } else {
+    // On se rend au dernier jour travaillé disponible
+    const lastWorkDay = getNearestWorkDay(date);
     const att = document.createTextNode(
       `Le jour sélectionné (${formatDate(date)}) n'est pas un jour travaillé.`
     );
-    openAlertModal("Erreur", att, "", "crimson");
-    dateInput.value = dateInput.getAttribute("value");
-    return false;
+    const div = document.createElement("div");
+    div.appendChild(att);
+    div.appendChild(document.createElement("br"));
+    div.appendChild(
+      document.createTextNode(
+        `Le dernier jour travaillé disponible a été sélectionné : ${formatDate(
+          lastWorkDay
+        )}.`
+      )
+    );
+    openAlertModal("Attention", div, "", "#eec660");
+    dateInput.value = lastWorkDay.toISOString().split("T")[0];
+    dateStr = formatDate(lastWorkDay).capitalize();
   }
+  document.querySelector("#datestr").textContent = dateStr;
+  return true;
+}
+
+function getNearestWorkDay(date) {
+  const aDay = 86400000; // 24 * 3600 * 1000 | H * s * ms
+  let day = date;
+  let count = 0;
+  while (verifyNonWorkDays(day.getDay(), nonWorkDays) && count++ < 7) {
+    day = new Date(day - aDay);
+  }
+  return day;
 }
 
 function verifyDateInSemester() {
diff --git a/app/templates/assiduites/pages/signal_assiduites_etud.j2 b/app/templates/assiduites/pages/signal_assiduites_etud.j2
index 7dc6cc3bb5..7a55c7a9ed 100644
--- a/app/templates/assiduites/pages/signal_assiduites_etud.j2
+++ b/app/templates/assiduites/pages/signal_assiduites_etud.j2
@@ -126,7 +126,6 @@
         function setTimeLineTimes(a, b) {
             setPeriodValues(a, b);
             updateJustifyBtn();
-
         }
 
         window.forceModule = "{{ forcer_module }}"