$.cookie(key,value,{path:"/",expires:7})后面{}里的是什么属性

  <script type="text/javascript">
            $(function () {
//          	console.log(111)
                if ($.cookie("email")) {
                    $("#email").val($.cookie('email'));
                }
                $("#btnSet").bind("click", function () {
                    if ($("#chksave").is(":checked")) {
                        $.cookie('email',$('#email').val()
                 	)
                    console.log($.cookie('email'));
                    }
                    else {
                        $.cookie('email',null)
                    }
                });
            });
        </script>