Using the JS fullscreen API is painful because all browers use different methods and events and you need to use lots of boilerplate code to make your application work in all browsers.
The "screenfull" library wraps that for you, including events.
The linked GitHub repo contains some information. You basically use the library like this:
// Make an element go fullscreen screenfull.request(element) // Leave fullscreen screenfull.exit() // Detect if something is currently fullscreen screenfull.isFullscreen // Register event when going fullscreen screenfull.on('change', functionCallback) // Get element that is currently fullscreening screenfull.element // De-register event screenfull.off('change', functionCallback)
Note that no jQuery is required even though
off may look like jQuery.