CSS: Make sure elem.ownerDocument.defaultView is not null

Fixes gh-2866
Close gh-2867

diff --git a/src/css/curCSS.js b/src/css/curCSS.js
index 67fc27525031a24db5800d49d9b7488ae5a5ab8e..8a01e2f740dd9be4a9ba57213a048e69bfd40714 100644 (file)
--- a/src/css/curCSS.js
+++ b/src/css/curCSS.js
@@ -19,7 +19,7 @@ if ( window.getComputedStyle ) {
                // FF meanwhile throws on frame elements through "defaultView.getComputedStyle"
                var view = elem.ownerDocument.defaultView;
 
-               if ( !view.opener ) {
+               if ( !view || !view.opener ) {
                        view = window;
                }