function exitFullscreen() {
            if (document.exitFullscreen) {
              document.exitFullscreen();
            } else if (document.mozCancelFullScreen) {
              document.mozCancelFullScreen();
            } else if (document.webkitExitFullscreen) {
              document.webkitExitFullscreen();
            } else if (document.msExitFullscreen) {
              document.msExitFullscreen();
            }
          }
Gets the current URL. Note: when using the
p5 Editor, this will return an empty object because the sketch
is embedded in an iframe. It will work correctly if you view the
sketch using the editor's present or share URLs.
@method getURL
@return {String} url
@example
<div>
<code>
let url;
let x = 100;

function setup() {
  fill(0);
  noStroke();
  url = getURL();
}

function draw() {
  background(200);
  text(url, x, height / 2);
  x--;
}
</code>
</div>

@alt
current url (http://p5js.org/reference/#/p5/getURL) moves right to left.