Allow past date in date/time field

[Martines]

Hi community, 

I'm struggling with creating the date/time field where only the past dates are allowed.  I found this code. 

But it doesn't work. The accepted behavior is that user is not able to choose from the date/time component the future dates. (This would be happy case) Or at least when user choose date in future he will get the message that future dates are not allowed. 

Do you have any suggestions? Thank you in advance. 

[Ankur Bawiskar]

@Martines 

Your script won't help user to know which field actually was having invalid value.

If Start date is invalid then it will show error message besides all fields.

You will require separate UI policies for each field

Logic I already shared