define([

"../../core",
"../../selector"
// css is assumed

], function( jQuery ) {

return function( elem, el ) {
        // isHidden might be called from jQuery#filter function;
        // in that case, element will be second argument
        elem = el || elem;
        return jQuery.css( elem, "display" ) === "none" || !jQuery.contains( elem.ownerDocument, elem );
};

});