Error Trapping, to prevent blank records/fields.

Anyone could help me with error-trapping script.

I would like to have to set up a script which will show dialog box when i left the "Date Billed" empty records.

After the dialog box, that only shows Ok button, then go back to the layout and go to the field (Date Billed), for the user to fill the records.

I would like to  apply this in all my fields that is required fields. instead of the filemaker error message ,i'd like to do it in a script.

i have attached my script which is continues to save even if the show dialog opens with (Revert Records,Yes,No) options, I would like to have a show dialog box with just ok button if the is empty field is True.