Vielen Dank für die Antwort!
Wäre dieser Code dann richtig, wenn ich zwei Wochen lang täglich drei Fragebogen verschicken möchte (wobei Montags jeweils der erste wegfällt)?:
mailSchedule(false, 2, strtotime('next Monday 14:00:00'));
mailSchedule(false, 3, strtotime('next Monday 21:00:00'));
mailSchedule(false, 4, strtotime('next Monday 06:00:00 +1day'));
mailSchedule(false, 5, strtotime('next Monday 14:00:00 +1day'));
mailSchedule(false, 6, strtotime('next Monday 21:00:00 +1day'));
mailSchedule(false, 7, strtotime('next Monday 06:00:00 +2days'));
mailSchedule(false, 8, strtotime('next Monday 14:00:00 +2days'));
mailSchedule(false, 9, strtotime('next Monday 21:00:00 +2days'));
mailSchedule(false, 10, strtotime('next Monday 06:00:00 +3days'));
mailSchedule(false, 11, strtotime('next Monday 14:00:00 +3days'));
mailSchedule(false, 12, strtotime('next Monday 21:00:00 +3days'));
mailSchedule(false, 13, strtotime('next Monday 06:00:00 +4days'));
mailSchedule(false, 14, strtotime('next Monday 14:00:00 +4days'));
mailSchedule(false, 15, strtotime('next Monday 21:00:00 +4days'));
mailSchedule(false, 16, strtotime('next Monday 14:00:00 +7days'));
mailSchedule(false, 17, strtotime('next Monday 21:00:00 +7days'));
mailSchedule(false, 18, strtotime('next Monday 06:00:00 +8days'));
mailSchedule(false, 19, strtotime('next Monday 14:00:00 +8days'));
mailSchedule(false, 20, strtotime('next Monday 21:00:00 +8days'));
mailSchedule(false, 21, strtotime('next Monday 06:00:00 +9days'));
mailSchedule(false, 22, strtotime('next Monday 14:00:00 +9days'));
mailSchedule(false, 23, strtotime('next Monday 21:00:00 +9days'));
mailSchedule(false, 24, strtotime('next Monday 06:00:00 +10days'));
mailSchedule(false, 25, strtotime('next Monday 14:00:00 +10days'));
mailSchedule(false, 26, strtotime('next Monday 21:00:00 +10days'));
mailSchedule(false, 27, strtotime('next Monday 06:00:00 +11days'));
mailSchedule(false, 28, strtotime('next Monday 14:00:00 +11days'));
mailSchedule(false, 29, strtotime('next Monday 21:00:00 +11days'));