diff --git a/testing/web-platform/tests/css/cssom-view/screenLeftTop.html b/testing/web-platform/tests/css/cssom-view/screenLeftTop.html
new file mode 100644
index 0000000000000..dcd97ebc79a99
--- /dev/null
+++ b/testing/web-platform/tests/css/cssom-view/screenLeftTop.html
@@ -0,0 +1,196 @@
+<
+!
+DOCTYPE
+html
+>
+<
+link
+rel
+=
+"
+help
+"
+href
+=
+"
+https
+:
+/
+/
+drafts
+.
+csswg
+.
+org
+/
+cssom
+-
+view
+/
+#
+dom
+-
+window
+-
+screenleft
+"
+>
+<
+link
+rel
+=
+"
+help
+"
+href
+=
+"
+https
+:
+/
+/
+drafts
+.
+csswg
+.
+org
+/
+cssom
+-
+view
+/
+#
+dom
+-
+window
+-
+screentop
+"
+>
+<
+script
+src
+=
+"
+/
+resources
+/
+testharness
+.
+js
+"
+>
+<
+/
+script
+>
+<
+script
+src
+=
+"
+/
+resources
+/
+testharnessreport
+.
+js
+"
+>
+<
+/
+script
+>
+<
+script
+>
+test
+(
+(
+)
+=
+>
+{
+assert_equals
+(
+typeof
+window
+.
+screenLeft
+"
+number
+"
+"
+screenLeft
+type
+"
+)
+;
+assert_equals
+(
+window
+.
+screenLeft
+window
+.
+screenX
+"
+alias
+of
+screenX
+"
+)
+;
+}
+"
+screenLeft
+"
+)
+;
+test
+(
+(
+)
+=
+>
+{
+assert_equals
+(
+typeof
+window
+.
+screenTop
+"
+number
+"
+"
+screenTop
+type
+"
+)
+;
+assert_equals
+(
+window
+.
+screenTop
+window
+.
+screenY
+"
+alias
+of
+screenY
+"
+)
+;
+}
+"
+screenTop
+"
+)
+;
+<
+/
+script
+>