How this browser alarm keeps time
When you set an alarm, the page stores the exact moment it should ring. The visible countdown is calculated from that deadline whenever the screen updates. It does not count browser timer ticks, which may slow down in a hidden tab.
The selected time uses your device's local clock. If you change the device time or time zone after setting the alarm, cancel it and set it again.
Before you rely on it
Deadline-based timing
The display recalculates from the stored target instead of counting browser ticks.
One local alarm
A new time replaces the current alarm; repeating schedules are not stored.
Keep the page open
Closing the tab or browser ends the alarm, and a sleeping page may delay sound.
Test the sound before using the alarm
Browsers normally require a click or tap before a page can play audio. Setting the alarm prepares its three-note alert, and the Test sound button lets you confirm that the browser and device can play it. Check your system volume too.
How to set an alarm
Choose a local time
If that time has passed today, the page schedules it for tomorrow.
Press Set alarm
Confirm the exact day and time shown beside the countdown.
Keep the page open
Stop the alarm when it rings, or snooze it for five minutes.
What happens in a hidden tab
The deadline remains the same when you switch tabs, and the page checks it as soon as the browser lets the page run again. A hidden or sleeping page can still be suspended, so the sound may be late. Keep the alarm visible when timing is critical.
A supported browser may keep the screen awake while the alarm is armed, but wake lock can be denied or released. Closing the tab or browser ends the alarm. This page does not schedule operating-system notifications, save alarms, or sync them to an account.
Frequently asked questions
Will the alarm ring if I close the browser?
No. The alarm runs only in this open page. Use the alarm app built into your phone or computer when you need an alert that survives a closed browser or device restart.
Can I set more than one alarm?
This version holds one alarm at a time. Setting a new time replaces the current alarm. It has no repeating schedule or saved alarm list.
Why did the alarm sound late?
A browser can suspend a hidden tab or the whole page while a device sleeps. The absolute deadline keeps the displayed target correct, but the page cannot make sound until the browser runs it again.
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