How can I prevent iPhone (including iOS 7) from going to sleep in HTML or JS?

How can I prevent iPhone (including iOS 7) from going to sleep in HTML or JS?

I'm attempting to write some code to keep a phone alive and not go to
sleep on a webpage.
In my search, I found this post: Prevent iOS mobile safari from going idle
/ auto-locking / sleeping?
But looping an audio file seems to no longer keep MobileSafari alive and
prevent the phone from locking. While forcing the page to refresh every 30
seconds works, I need the original page to stay open.
Google's latest interactive music video, Just A Reflektor, seems to be
preventing lock from mobile, and their JS here references a
preventSleepIos function.
What could I simply do to prevent iOS from falling asleep?
Thanks!