// get with web apis #fullscren element and on click toggle fullscreen const fullscreen = document.getElementById('fullscreen'); const elem = document.documentElement; fullscreen.addEventListener('click', () => { if (document.fullscreenElement) { closeFullscreen(); } else { openFullscreen(); } }); function openFullscreen() { if (elem.requestFullscreen) { elem.requestFullscreen(); } else if (elem.webkitRequestFullscreen) { /* Safari */ elem.webkitRequestFullscreen(); } else if (elem.msRequestFullscreen) { /* IE11 */ elem.msRequestFullscreen(); } } function closeFullscreen() { if (document.exitFullscreen) { document.exitFullscreen(); } else if (document.webkitExitFullscreen) { /* Safari */ document.webkitExitFullscreen(); } else if (document.msExitFullscreen) { /* IE11 */ document.msExitFullscreen(); } }