diff --git a/src/css.js b/src/css.js
index 86399aa51..f2c0473dd 100644
--- a/src/css.js
+++ b/src/css.js
@@ -291,7 +291,7 @@ jQuery.extend({
 // because jsdom on node.js will break without it.
 if ( window.getComputedStyle ) {
 	getStyles = function( elem ) {
-		return window.getComputedStyle( elem, null );
+		return elem.ownerDocument.defaultView.getComputedStyle( elem, null );
 	};
 
 	curCSS = function( elem, name, _computed ) {