Onload event is not firing on new appointment in Outlook 2016 for CRM 365

Hi..I have following java script code in Appointment 

alert(1);

function appointmentOnLoad() {

alert('on load');

}

alert(2);

I see all three alert in web browser(IE) when i click new appointment but When I try  the same  in Outlook 2016 plugin  i only see two alert . the alert inside "appointmentOnLoad" is not firing. However, once the appointment is saved, I can see all three alert upon opening the record. It is only happening in new form for outlook client.  Does anybody know what is the reason?