Keep Awake

What it's for

Stop the screen dimming, going to sleep or locking while you need it, without installing anything or changing your settings, using the browser’s Screen Wake Lock, the same feature video sites use while a video plays. It does what apps such as Caffeine and Amphetamine do on the Mac, for as long as this tab is open.

For example, when you’re presenting from a browser, following a recipe on a tablet or keeping a dashboard on a spare screen, open this page in a tab beside it and press Keep this screen awake.

How to use it

Press Keep this screen awake, and press it again (now Let it sleep) to stop. To stop by itself, set Stop after to a number of minutes first; 0 keeps it going until you stop it. The message says whether it’s working and for how long so far. If you switch to another tab or app, the browser lets go, and it’s taken again when you come back to this tab. The time limit is remembered in this browser.

Example

Set Stop after to 1 and press Keep this screen awake. The message reads:

Keeping the screen awake. It stops if you close or hide this tab.

A minute later it reads “Stopped after 1 minute: the screen can sleep again.”

Good to know

It only works while this tab is open and in view: another tab or window in front, a minimised window, or closing the page lets the screen sleep. It keeps the screen on, not the computer awake for downloads in the background. The browser can refuse, for example on a low battery or in battery saver mode, and some older browsers don’t support it; the message says so. Locking the screen yourself still works.