1 files changed, 2 insertions, 1 deletions
diff --git a/testing/web-platform/tests/navigation-api/navigate-event/navigate-navigation-navigate.html b/testing/web-platform/tests/navigation-api/navigate-event/navigate-navigation-navigate.html
index c56af1b40d..5dd1892cc0 100644
--- a/testing/web-platform/tests/navigation-api/navigate-event/navigate-navigation-navigate.html
+++ b/testing/web-platform/tests/navigation-api/navigate-event/navigate-navigation-navigate.html
@@ -16,7 +16,8 @@ async_test(t => {
     assert_equals(e.destination.id, "");
     assert_equals(e.destination.index, -1);
     assert_equals(e.formData, null);
-    assert_equals(e.sourceElement, null);
+    // NavigateEvent sourceElement is still in development, so test whether it is available.
+    if ("sourceElement" in e) assert_equals(e.sourceElement, null);
   });
   navigation.navigate("#foo");
 }, "navigate event for navigation.navigate()");