How to add validation rule to date and time field

Question

Hi, I need to make a validation of one form field, user enters start date-and-time and end date-and-time and then needs to enter an integer number, I have to validate on the form that the entered number is smaller or equal to the difference of end date-and-time minus start date-and-time? I created a JS that throws an alert if the entered number is larger, but I still can not validate the field and prevent the user from submitting the form. Can I somehow use the output from "Event rule" for validation? Help please? 
 OriginalPostID-22392 
 OriginalPostID-22392

Eduardo Fuentes · Accepted Answer

You need to add a validation rule to the field. Review this link for more information: forum.appian.com/.../Form_Validation

Carlos Santander · Answer

The link that was provided (from a few years ago) was for Appian 6.6, which was before SAIL. A more relevant page nowadays might be docs.appian.com/.../recipe_showing_validation_errors_that_arent_specific_to_one_component.html .