SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd");
Date birthday = ft.parse("2020-05-01");
v.val(birthday, "older than 18"); // false
Date birthday2 = ft.parse("1980-05-01");
v.val(birthday2, "older than 18"); // true
可以用RebbVal的内置函数date()来将字符串快捷的转换成日期
v.val(v.date("1980-12-01"), "older than 21"); // true
年轻于 Younger than
SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd");
Date birthday = ft.parse("2020-05-01");
v.val(birthday, "younger than 18"); // true
v.val(v.date("1980-01-01"), "younge than 18"); // false