在引导程序中禁用上一个按钮

像这样旅游

var TourToolTipPoolConfiguration = new Tour({
            name: 'TourToolTipPoolConfiguration',
            steps: [
                {
                    onNext: function (TourToolTipPoolConfiguration) {
                        TourToolTipPoolConfiguration.goTo(3);
                    },
                    element: "#TimeExpireTicket",
                    title: "foo",
                    content: "test1"
                },
                {
                    element: "#DayNumber",
                    title: "foo",
                    content: "test2"
                },
                {
                    element: "#SavePoolConfig",
                    title: "foo",
                    content: "test3"
                }
            ]
        });

步骤1或步骤2是可选的,我隐藏了div显示:none,但如果在步骤2中tour init,我需要禁用prev按钮,因为步骤1是隐藏的,如何做到这一点?如果div可见但不起作用,我尝试使用prev evaluate