diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index f39a8b44904..7623a1a6a46 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -24766,7 +24766,7 @@
    "support"
   ],
   "css/offset_properties_inline.html": [
-   "e879ede3d52eed5ebdd90e988380ba4fa365817a",
+   "ed9cf0062ff6b08dc0cc578a0ae6acce146bec10",
    "testharness"
   ],
   "css/ol_japanese_iroha_a.html": [
diff --git a/tests/wpt/mozilla/tests/css/offset_properties_inline.html b/tests/wpt/mozilla/tests/css/offset_properties_inline.html
index cb88fa3a246..9b93cde7fc0 100644
--- a/tests/wpt/mozilla/tests/css/offset_properties_inline.html
+++ b/tests/wpt/mozilla/tests/css/offset_properties_inline.html
@@ -30,6 +30,7 @@
   -->
 </div>
 <script>
+window.onload = function() {
   var realOffsetParent = document.getElementById('real-offset-parent');
   var inline1 = document.getElementById('inline-1');
   var inline2 = document.getElementById('inline-2');
@@ -79,5 +80,6 @@
     assert_equals(inline3.offsetHeight, 10,
       "offsetHeight of #inline-3 should be 10.");
   }, "offsetHeight");
+}
 </script>
 </body>