//Additional selectors
$.extend($.expr[':'], {
	data: function(elem, i, match) {
		return !!$.data(elem, match[3]);
	},

	focusable: function(element) {
		var nodeName = element.nodeName.toLowerCase(),
			tabIndex = $.attr(element, 'tabindex');
		return (/input|select|textarea|button|object/.test(nodeName)
			? !element.disabled
			: 'a' == nodeName || 'area' == nodeName
				? element.href || !isNaN(tabIndex)
				: !isNaN(tabIndex))
			// the element and all of its ancestors must be visible
		    // the browser may report that the area is hidden
			// delete base node,base in IE6 have broker,by fredli
			&& !$(element)['area' == nodeName ? 'parents' : 'closest'](':hidden').not('Base').length;
	},

	tabbable: function(element) {
		var tabIndex = $.attr(element, 'tabindex');
		return (isNaN(tabIndex) || tabIndex >= 0) && $(element).is(':focusable');
	}
});