In an iOS app you can set application.idleTimerDisabled = YES
to prevent the phone from auto locking.
I need to do this in mobile safari for a game li
Edit: This work around no longer works. It is not currently possible to prevent the phone from sleeping in safari.
Yes, you can prevent the phone to sleep using an audio loop. The trick won't start automatically, you will have to play it when the visitor touches the screen.
Test page: tap play and the display will stay on but it will dim on some devices, like an iPhone with iOS 7.
Note: be careful using this trick because it will stop any music that the visitors might be using—and it will annoy them.