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 );
	};
} );
 
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