Standard validation functions

There are some standard custom validation functions that are available for use.

std:validation:compare_to_today

This compares the value input into the date element you are defining to today, according to the data passed in:

operation The operation to use, one of < or >. The current value takes the left hand side of the operation.
delta A positive or negative integer offset in days. Optional.
errorMessage An error message to be displayed in the event of failed validation. Recommended.

std:validation:compare_to_date

This compares the value input into the date element you are defining to another date value, according to the data passed in:

path The path of the date the current value should be compared to. Must be defined in the document before the current path. One of path or externalData must be defined.
externalData The property in external data the current value should be compared to.
operation The operation to use, one of < or >. The current value takes the left hand side of the operation.
delta A positive or negative integer offset in days. Optional.
errorMessage An error message to be displayed in the event of failed validation. Recommended.