diff --git a/public/js/lufi-down.js b/public/js/lufi-down.js
index af98a41..142c9e1 100644
--- a/public/js/lufi-down.js
+++ b/public/js/lufi-down.js
@@ -71,7 +71,7 @@ function spawnWebsocket() {
                 pbd.innerHTML = '<a href="'+URL.createObjectURL(blob)+'" class="btn btn-primary" download="'+data.name+'">'+i18n.download+'</a>';
 
                 ws.send('{"ended":true}');
-                window.onbeforeunload = null;
+                window.removeEventListener('onbeforeunload', confirmExit);
             } else {
                 if (ws.readyState === 3) {
                     ws = spawnWebsocket();
@@ -93,5 +93,5 @@ document.addEventListener('DOMContentLoaded', function() {
     ws = spawnWebsocket();
 
     // Prevent exiting page before full download
-    window.onbeforeunload = confirmExit;
+    window.addEventListener('onbeforeunload', confirmExit);
 });
diff --git a/public/js/lufi-up.js b/public/js/lufi-up.js
index 9057099..9aaf6c6 100644
--- a/public/js/lufi-up.js
+++ b/public/js/lufi-up.js
@@ -96,7 +96,7 @@ function handleFiles(f) {
 // Create progress bar and call slicing and uploading function
 function uploadFile(i, delay, del_at_first_view) {
     // Prevent exiting page before full upload
-    window.onbeforeunload = confirmExit;
+    window.addEventListener('onbeforeunload', confirmExit);
 
     // Create a random key, different for all files
     var randomkey = sjcl.codec.base64.fromBits(sjcl.random.randomWords(8, 0), 0);
@@ -233,7 +233,7 @@ function updateProgressBar(data) {
             uploadFile(i, delay, del_at_first_view);
         } else {
             // We have finished
-            document.onbeforeunload = null;
+            window.removeEventListener('onbeforeunload', confirmExit);
             document.getElementById('delete-day').removeAttribute('disabled');
             document.getElementById('first-view').removeAttribute('disabled');
         }