In Ramadan the night has a hard edge at dawn, and the household plans backwards from it — the meal, the washing up, the last glass of water. If 12:22 am is the figure you are working to, this page counts down to it exactly, second by second, instead of leaving the arithmetic to somebody who has been awake since midnight.
There is nothing to start and nothing to choose. The page reads the clock on your device, works out the gap to 12:22 am, and redraws it every second for as long as it is open. Leave it in a background tab if you like; the number will be current whenever you look back at it.
Plenty of phones and dashboards default to a 24-hour display regardless of how people around them actually speak, so 00:22 may well be the figure staring back at you while 12:22 am is what anyone would say out loud. Neither form is more correct; they are just aimed at different readers.
Common questions
What is 00:22 on a 12-hour clock?
The same instant is 12:22 am in writing and twenty-two minutes past twelve at night out loud. Anything from 13:00 onwards loses twelve to give the pm figure, which is the only sum involved in moving between the two.
Does the number update by itself?
Yes. It is recalculated every second from your device's clock, so nothing needs refreshing or restarting. Whatever is on screen is the current gap to 12:22 am, not a figure worked out when the page first opened.
What happens once 12:22 am has passed for today?
The count rolls over and carries on towards the same time tomorrow. That happens on its own at the moment the time passes — the page does not need reloading and there is nothing to reset by hand.
Which clock does the countdown use?
Your own. It reads the local time and time zone from the device in front of you, which in the Emirates means Gulf Standard Time, UTC+4. Travel and the count follows whatever the device picks up.