fullscreen mode javascript
//creating a button and linking it to bClicked()
document.onload=()=>{
let b = documentbody.createElement("button");
b.onclick = bClicked;
}
function bClicked(){
//yourID is the id of element that you want to fullscreen
document.getElementByID("yourID").requestFullscreen();
}
//to exit fullscreen
document.exitFullscreen();