diff --git a/app/static/app.js b/app/static/app.js
index 97d886d..dfa8537 100644
--- a/app/static/app.js
+++ b/app/static/app.js
@@ -283,8 +283,9 @@ function submitPdf(eve) {
   submitForm(formdata);
 }
 async function submitForm(formData) {
+  var updateEventSource = None;
   try {
-    const updateEventSource = new EventSource("/get_censor_status/" + doc.fID);
+    updateEventSource = new EventSource("/get_censor_status/" + doc.fID);
 
     modal.style.display = "flex";
     // console.log("http://127.0.0.1:8000/get_censor_status/" + doc.fID);
@@ -304,7 +305,9 @@ async function submitForm(formData) {
       method: "POST",
       body: formData,
     });
-    updateEventSource.close();
+    if (updateEventSource !== None) {
+      updateEventSource.close();
+    }
     modal.style.display = "none";
     //let responseJSON=await response.json();
     if (response.ok) {