diff --git a/Libraries/LibWeb/HTML/ErrorEvent.h b/Libraries/LibWeb/HTML/ErrorEvent.h
index 59a87f9623..296b7958c6 100644
--- a/Libraries/LibWeb/HTML/ErrorEvent.h
+++ b/Libraries/LibWeb/HTML/ErrorEvent.h
@@ -17,7 +17,7 @@ struct ErrorEventInit : public DOM::EventInit {
     String filename;
     u32 lineno { 0 };
     u32 colno { 0 };
-    JS::Value error { JS::js_null() };
+    JS::Value error { JS::js_undefined() };
 };
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#errorevent
diff --git a/Libraries/LibWeb/HTML/ErrorEvent.idl b/Libraries/LibWeb/HTML/ErrorEvent.idl
index 874cd60b33..38d758c0d9 100644
--- a/Libraries/LibWeb/HTML/ErrorEvent.idl
+++ b/Libraries/LibWeb/HTML/ErrorEvent.idl
@@ -12,10 +12,11 @@ interface ErrorEvent : Event {
     readonly attribute any error;
 };
 
+// https://html.spec.whatwg.org/#erroreventinit
 dictionary ErrorEventInit : EventInit {
     DOMString message = "";
     USVString filename = "";
     unsigned long lineno = 0;
     unsigned long colno = 0;
-    any error = null;
+    any error;
 };
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.txt b/Tests/LibWeb/Text/expected/wpt-import/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.txt
new file mode 100644
index 0000000000..5c014ded09
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.txt
@@ -0,0 +1,10 @@
+Harness status: OK
+
+Found 5 tests
+
+5 Pass
+Pass	error event is normal (return true does not cancel; one arg) on Document, with a synthetic ErrorEvent
+Pass	Initial values of ErrorEvent members
+Pass	error member can be set to null
+Pass	error member can be set to undefined
+Pass	error member can be set to arbitrary
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.html b/Tests/LibWeb/Text/input/wpt-import/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.html
new file mode 100644
index 0000000000..e0df4394d6
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.html
@@ -0,0 +1,60 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Event handlers processing algorithm: error events</title>
+<script src="../../../../../resources/testharness.js"></script>
+<script src="../../../../../resources/testharnessreport.js"></script>
+<link rel="help" href="https://html.spec.whatwg.org/multipage/#the-event-handler-processing-algorithm">
+<link rel="author" title="Domenic Denicola" href="mailto:d@domenic.me">
+
+<div id="log"></div>
+
+<script>
+"use strict";
+setup({ allow_uncaught_exception: true });
+
+promise_test(t => {
+  document.onerror = t.step_func((...args) => {
+    assert_equals(args.length, 1);
+    return true;
+  });
+
+  const eventWatcher = new EventWatcher(t, document, "error");
+  const promise = eventWatcher.wait_for("error").then(e => {
+    assert_equals(e.defaultPrevented, false);
+    assert_equals(e.message, "");
+    assert_equals(e.filename, "");
+    assert_equals(e.lineno, 0);
+    assert_equals(e.colno, 0);
+    assert_equals(e.error, undefined);
+  });
+
+  document.dispatchEvent(new ErrorEvent("error", { cancelable: true }));
+
+  return promise;
+}, "error event is normal (return true does not cancel; one arg) on Document, with a synthetic ErrorEvent");
+
+test(() => {
+  const e = new ErrorEvent("error");
+  assert_equals(e.message, "");
+  assert_equals(e.filename, "");
+  assert_equals(e.lineno, 0);
+  assert_equals(e.colno, 0);
+  assert_equals(e.error, undefined);
+}, "Initial values of ErrorEvent members")
+
+test(() => {
+  const e = new ErrorEvent("error", {error : null});
+  assert_equals(e.error, null);
+}, "error member can be set to null")
+
+test(() => {
+  const e = new ErrorEvent("error", {error : undefined});
+  assert_equals(e.error, undefined);
+}, "error member can be set to undefined")
+
+test(() => {
+  const e = new ErrorEvent("error", {error : "foo"});
+  assert_equals(e.error, "foo");
+}, "error member can be set to arbitrary")
+
+</script>
