diff --git a/app/error-handler.js b/app/error-handler.js
index f956c224..e9ce68ec 100644
--- a/app/error-handler.js
+++ b/app/error-handler.js
@@ -6,67 +6,57 @@
  * See README.md for usage and integration instructions.
  */
 
-// NB: this should *not* be included as a module until we have
-// native support in the browsers, so that our error handler
-// can catch script-loading errors.
+// Fallback for all uncought errors
+function handleError(event, err) {
+    try {
+        const msg = document.getElementById('noVNC_fallback_errormsg');
 
-// No ES6 can be used in this file since it's used for the translation
-/* eslint-disable prefer-arrow-callback */
-
-(function _scope() {
-    "use strict";
-
-    // Fallback for all uncought errors
-    function handleError(event, err) {
-        try {
-            const msg = document.getElementById('noVNC_fallback_errormsg');
-
-            // Work around Firefox bug:
-            // https://bugzilla.mozilla.org/show_bug.cgi?id=1685038
-            if (event.message === "ResizeObserver loop completed with undelivered notifications.") {
-                return false;
-            }
-
-            // Only show the initial error
-            if (msg.hasChildNodes()) {
-                return false;
-            }
-
-            let div = document.createElement("div");
-            div.classList.add('noVNC_message');
-            div.appendChild(document.createTextNode(event.message));
-            msg.appendChild(div);
-
-            if (event.filename) {
-                div = document.createElement("div");
-                div.className = 'noVNC_location';
-                let text = event.filename;
-                if (event.lineno !== undefined) {
-                    text += ":" + event.lineno;
-                    if (event.colno !== undefined) {
-                        text += ":" + event.colno;
-                    }
-                }
-                div.appendChild(document.createTextNode(text));
-                msg.appendChild(div);
-            }
-
-            if (err && err.stack) {
-                div = document.createElement("div");
-                div.className = 'noVNC_stack';
-                div.appendChild(document.createTextNode(err.stack));
-                msg.appendChild(div);
-            }
-
-            document.getElementById('noVNC_fallback_error')
-                .classList.add("noVNC_open");
-        } catch (exc) {
-            document.write("noVNC encountered an error.");
+        // Work around Firefox bug:
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=1685038
+        if (event.message === "ResizeObserver loop completed with undelivered notifications.") {
+            return false;
         }
-        // Don't return true since this would prevent the error
-        // from being printed to the browser console.
-        return false;
+
+        // Only show the initial error
+        if (msg.hasChildNodes()) {
+            return false;
+        }
+
+        let div = document.createElement("div");
+        div.classList.add('noVNC_message');
+        div.appendChild(document.createTextNode(event.message));
+        msg.appendChild(div);
+
+        if (event.filename) {
+            div = document.createElement("div");
+            div.className = 'noVNC_location';
+            let text = event.filename;
+            if (event.lineno !== undefined) {
+                text += ":" + event.lineno;
+                if (event.colno !== undefined) {
+                    text += ":" + event.colno;
+                }
+            }
+            div.appendChild(document.createTextNode(text));
+            msg.appendChild(div);
+        }
+
+        if (err && err.stack) {
+            div = document.createElement("div");
+            div.className = 'noVNC_stack';
+            div.appendChild(document.createTextNode(err.stack));
+            msg.appendChild(div);
+        }
+
+        document.getElementById('noVNC_fallback_error')
+            .classList.add("noVNC_open");
+    } catch (exc) {
+        document.write("noVNC encountered an error.");
     }
-    window.addEventListener('error', function onerror(evt) { handleError(evt, evt.error); });
-    window.addEventListener('unhandledrejection', function onreject(evt) { handleError(evt.reason, evt.reason); });
-})();
+    // Don't return true since this would prevent the error
+    // from being printed to the browser console.
+    return false;
+}
+
+window.addEventListener('error', evt => handleError(evt, evt.error));
+window.addEventListener('unhandledrejection', evt => handleError(evt.reason, evt.reason));
diff --git a/vnc.html b/vnc.html
index 8d4b4979..d8c0b7ec 100644
--- a/vnc.html
+++ b/vnc.html
@@ -55,7 +55,7 @@
     <link rel="preload" as="image" href="app/images/error.svg">
     <link rel="preload" as="image" href="app/images/warning.svg">
 
-    <script src="app/error-handler.js"></script>
+    <script type="module" crossorigin="anonymous" src="app/error-handler.js"></script>
     <script type="module" crossorigin="anonymous" src="app/ui.js"></script>
 </head>