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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 );

        };

});