1 files changed, 4 insertions, 2 deletions
diff --git a/testing/web-platform/tests/navigation-api/navigate-event/event-constructor.html b/testing/web-platform/tests/navigation-api/navigate-event/event-constructor.html
index 863681ced7..89ac934020 100644
--- a/testing/web-platform/tests/navigation-api/navigate-event/event-constructor.html
+++ b/testing/web-platform/tests/navigation-api/navigate-event/event-constructor.html
@@ -78,7 +78,8 @@ async_test(t => {
     assert_equals(event.downloadRequest, downloadRequest);
     assert_equals(event.info, info);
     assert_equals(event.hasUAVisualTransition, hasUAVisualTransition);
-    assert_equals(event.sourceElement, sourceElement);
+    // NavigateEvent sourceElement is still in development, so test whether it is available.
+    if ("sourceElement" in e) assert_equals(event.sourceElement, sourceElement);
   });
   history.pushState(2, null, "#2");
 }, "all properties are reflected back");
@@ -98,7 +99,8 @@ async_test(t => {
     assert_equals(event.formData, null);
     assert_equals(event.downloadRequest, null);
     assert_equals(event.info, undefined);
-    assert_equals(event.sourceElement, null);
+    // NavigateEvent sourceElement is still in development, so test whether it is available.
+    if ("sourceElement" in e) assert_equals(event.sourceElement, null);
   });
   history.pushState(3, null, "#3");
 }, "defaults are as expected");