The (trivial!) code snippet below does not work:

d = getField("Date1").value; day = d.getDay(); this.getField("Day").value = day;
I am trying to run this code snippet in a PDF Form document:
Line 1: reads a date from the Form’s Date Field “Date1” and saves it to d
Line 2: Gets the day of the week from d
Line 3: Inserts “day” in the Form’s numerical field “Day”

It does not work. What am I doing wrong there?
Thanks

I was expecting to see the day of the week (numerically) appear in the in the result (numerical) field.