This script prevents computer or display sleep with HTML5/JavaScript.

Include the sleep.js script in your page, then control the computer's sleep functionality by calling:

sleep.prevent()
sleep.allow()

These tables explains the ability of the script to prevent sleep in different scenarios.

Tested on the following browsers: Chrome 52, Firefox 46 and Safari 9. Firefox and Safari display an audio icon when sleep is being prevented.

                              |Chrome  |Firefox |Safari

----------------------------------|:------:|:------:|:------: Active tab |✔|✔|✘ Active tab; browser in background |✔|✔|✘ Active tab; browser minimised |✔|✘|✘ Background tab |✘|✘|✘

                              |Chrome  |Firefox |IE 9    |IE 10   |IE 11

----------------------------------|:------:|:------:|:------:|:------:|:------: Active tab |? |? |? |? |? Active tab; browser in background |? |? |? |? |? Active tab; browser minimised |? |? |? |? |? Background tab |? |? |? |? |?

This approach uses a small empty video that is inserted in the page, but off-screen, without sound, but importantly: with an audio track.

This hack in reality controls the video playback which is what makes the browser stay awake.

The video files are at these locations; make sure there are no problems accessing them:

https://github.com/ivanmaeder/computer-sleep/raw/master/resources/muted-blank.mp4

https://github.com/ivanmaeder/computer-sleep/raw/master/resources/muted-blank.ogv

Check that your browser supports these video formats.

Check that your browser normally stays awake when playing video.

http://stackoverflow.com/questions/10377453/play-infinitely-looping-video-on-load-in-html5

http://stackoverflow.com/questions/26896400/how-to-allow-system-sleep-on-non-fullscreen-html5-video

https://productforums.google.com/forum/#!msg/youtube/C72RHsRYDpo/XE15rBP3gZUJ