I would like to share a FormPage I created that computes the ISO weekdate. The ISO weekdate system uses only weeks and no months. I used the following code to create a FormPage at https://www.wolframcloud.com/obj/9d2b09f3-50c9-4941-af17-16183e2f43c5:

ISOWeekDayDateFormPage = 
 CloudDeploy[
  FormPage[{"date" -> "ComputedDate"}, 
   StringTemplate[
      "<* DateValue[#1,\"Year\"] *>-W<* DateValue[#1,\"ISOWeek\"] \
*>-<* DateValue[#1,\"ISOWeekDay\"] *>"
              ][#date] &], Permissions -> "Public"]
SystemOpen[ISOWeekDayDateFormPage]

I also did some investigation in a notebook I would like to share: