$.extend($.expr[":"], {
	// [url]http://docs.jquery.com/Plugins/Validation/blank[/url]
	blank: function(a) {return !$.trim("" + a.value);},
	// [url]http://docs.jquery.com/Plugins/Validation/filled[/url]
	filled: function(a) {return !!$.trim("" + a.value);},
	// [url]http://docs.jquery.com/Plugins/Validation/unchecked[/url]
	unchecked: function(a) {return !a.checked;}
});