How to exit fullscreen onclick using Javascript?

Question

Not sure if the following code snip will work embedded on SO, as it didn\'t work when pasting it, however it does work stand-alone.

The problem, is I want this to be a t

Answer 1

A more generalized helper (derived from the accepted answer)...

Get Mode

The function can be invoked without arguments to find out if the browser is currently in Fullscreen Mode. It returns true if so and false otherwise.

Set Mode

The function can be invoked with a bool to explicitly set the current mode, where true ensures the browser is in Fullscreen Mode, and false ensures it isn't.

Toggle Mode

The function can be invoked with null as the only argument to implicitly set the mode to the opposite of whatever mode it is currently in.

---

let fullscreen = function() {

    let enter = function() {
        let body = document.body;
        if (body.requestFullscreen) body.requestFullscreen();
        else if (body.webkitRequestFullscreen) body.webkitRequestFullscreen();
        else if (body.mozRequestFullScreen) body.mozRequestFullScreen();
        else if (body.msRequestFullscreen) body.msRequestFullscreen();
    };

    let exit = function() {
        if (document.exitFullscreen) document.exitFullscreen();
        else if (document.webkitExitFullscreen) document.webkitExitFullscreen();
        else if (document.mozCancelFullScreen) document.mozCancelFullScreen();
        else if (document.msExitFullscreen) document.msExitFullscreen();
    };

    let attemptToGetState = element => element && element !== null;

    return function(action=undefined) {
        if (action === true) enter();
        else if (action === false) exit();
        else {
            let currentlyFullscreen = (
                attemptToGetState(document.fullscreenElement)       ||
                attemptToGetState(document.webkitFullscreenElement) ||
                attemptToGetState(document.mozFullScreenElement)    ||
                attemptToGetState(document.msFullscreenElement)
            );
            if (action === undefined) return !! currentlyFullscreen;
            else currentlyFullscreen ? exit() : enter();
        }
    };

}();