The addMilliseconds method returns a new DayPilot.Date value with the specified number of milliseconds added.
DayPilot.Date.addMilliseconds(milliseconds)milliseconds (number) - number of milliseconds to add.
The current value is not changed. The method returns a new DayPilot.Date object.
const start = new DayPilot.Date("2025-03-01T08:00:00.000");
const result = start.addMilliseconds(250);