The pips on the hour have been marking time for the best part of a century, and plenty of people still set their watch by the one o'clock signal without thinking about it. This page does something narrower and more exact: it counts down to 12:09 pm on your own device's clock, right down to the second.
Nothing is downloaded, nothing is registered, and nothing is left on the device afterwards. The whole count runs inside the page you already have open. Closing it costs nothing at all, and opening it again later simply shows the accurate gap to 12:09 pm as it stands at that moment.
Matching what somebody said against what somebody wrote is easier with all three versions to hand: 12:09 pm for everyday reading, 12:09 for anything printed in railway style, and nine minutes past twelve in the afternoon for whatever was actually spoken down the phone. All three describe precisely the same point in the day, and having them side by side saves a good deal of squinting at a timetable.
Common questions
Does the number update by itself?
Yes. It recalculates every second from your device's clock, so there is nothing to refresh or restart. Whatever is on screen is the current gap to the target time, not a figure worked out when the page first loaded.
What happens if 12:09 pm has already gone for today?
The count simply carries on towards the next occurrence, which is tomorrow. That rollover happens on its own — the page does not need reloading and there is nothing to reset by hand.
Which clock does it use?
Your own. It reads the local time and time zone from the device you are looking at, so the figure reflects where you actually are rather than a fixed zone written into the page.
Will this alert me when the time arrives?
No. It is a live number rather than an alarm — nothing rings, buzzes or notifies you at zero. If you need to be interrupted at 12:09 pm, set an alarm as well and treat this page as the running total.