How I can validate (in an input form) if a date field is filled in? I tried

Appian version is 6.6.1

Use an expression to check if the value meets your desired conditions. If not, loop back to the form with a chained gateway and display a show only if message to alert the user.

Thanks alex but, if is possible, I want make a validation direct on the input form without xor in process...

This method is preferred as it uses all out-of-the-box functionality and allows forms to be tempo/mobile enabled

Alex, You are right ! But I'm curious about other solutions (eg. FormApi ) :)

If you want to use JS, you can use the below code -
var selectedDate = FormAPI.getValue(selectedDateFieldId).id;
var selectedDateParts = selectedDate.split("/");
This will give you an array which contains, the date, month and year.

Akhilan, thanks. .. I'll try this solution :)

How I can check if one Date are filled or not?
I need to checking if the user filling a date in a form...

To stay out of the box, I would recommend following Alex's suggestion of using an Appian expression for the validation. If you want to use JS, then you could do a null check on the date field value inside your javascript to determine is a value was entered or not.