diff --git a/testharnessreport.js b/testharnessreport.js
index 4d8c9425a2d5ff..a57b4277600867 100644
--- a/testharnessreport.js
+++ b/testharnessreport.js
@@ -384,7 +384,10 @@ metadata_generator.setup();
  * default in-browser runner to configure the timeout and the
  * rendering of results
  */
-if (window.opener && "testharness_properties" in window.opener) {
-    setup(window.opener.testharness_properties);
+try {
+    if (window.opener && "testharness_properties" in window.opener) {
+        setup(window.opener.testharness_properties);
+    }
+} catch (e) {
 }
 // vim: set expandtab shiftwidth=4 tabstop=4: