name = name.replace( rupper, "-$1" ).toLowerCase();
- var computedStyle = elem.ownerDocument.defaultView.getComputedStyle( elem, null );
+ var defaultView = elem.ownerDocument.defaultView;
+
+ if ( !defaultView ) {
+ return null;
+ }
+
+ var computedStyle = defaultView.getComputedStyle( elem, null );
if ( computedStyle ) {
ret = computedStyle.getPropertyValue( name );