How to use the online alarm clock
As you finish up and head out, set the 10:01 pm alarm so the curtains are closed before darkness settles outside. That gives the reminder a clear purpose rather than leaving the job until you return or suddenly noticing it near 11:00 pm. Label the alarm “close curtains” so its meaning is obvious when it sounds.
Because you may move on to another page while finishing, keep this alarm page open in the background and leave sound enabled. Browsers can reduce activity in a background tab, although the alarm should remain ready while the browser and computer stay awake. If the browser is closed or the computer goes to sleep, the curtains reminder will not sound, so use a separate alarm if you will already have left.
Stepping outdoors after closing the curtains can feel quite different from the afternoon, particularly on a humid British evening. At 10:01 pm, check whether the air feels damp before leaving windows open behind the curtains; trapped moisture can make a room feel stuffy. If the outside air is fresher, a brief airing before you go may be useful, but secure the windows before leaving the property unattended.
Common questions
Will it still be right when the clocks change?
Yes. It reads your device's local clock, so the move between GMT and BST at the end of March and October is picked up automatically, as long as the computer's date, time and time zone are set correctly.
Can I use this on a phone?
It works in a mobile browser, but phones lock the screen and suspend background tabs far more readily than a laptop does, which can stop the alarm sounding. For anything important, a desktop or a plugged-in laptop is the steadier option.
Does the alarm still work if I close the tab?
No. Everything runs inside this page, so closing the tab — or quitting the browser altogether — ends the countdown there and then. Leaving it open in the background is all it asks, and switching to another tab makes no difference.
What happens if my laptop goes to sleep before 10:01 pm?
The tab sleeps along with it and the alarm will not sound on time, if at all. If you are relying on it, change the power settings so the machine stays awake, or keep a phone alarm running as well.