The OnClientAppointmentResizeStart client-side event is called before an appointment starts to resize.
Two parameters are passed to the event handler:
sender is the scheduler client object.
eventArgs has the following methods:
get_appointment() returns the appointment that is about to be resized.
set_cancel() lets you permit or block the resize of the appointment. Calling set_cancel(true) stops the resize, while set_cancel(false) allows the user to give the appointment a new duration.
This example prevents the user from resizing the "Planning Session" appointment but permits all other appointments to be resized: