Does anyone know how I can turn my JavaScript Clock into a deskstop screen saver?

Does anyone know how I can turn my JavaScript Clock into a deskstop screen saver? Link below…
I want to be able to use this my desktop screen saver for my computer and maybe even my phone… where to start?

https://ainneo.github.io/js-css-techo-clock/

Try:

if (document.fullscreenEnabled) {
  document.body.requestFullscreen();
}