var counter = 0;

async function reloadSlide() {
  const req = await fetch(`./slide/${counter}.html`)
  if(req.status != 200) return false;
  container.innerHTML = await req.text();
  return true;
}

async function nextSlide() {
  counter++;
  if(!await reloadSlide()) counter--;
}

async function previousSlide() {
  counter--;
  if(!await reloadSlide()) counter++;
}

document.body.addEventListener('click', nextSlide); 

document.addEventListener(
  "keydown",
  (event) => {
    if(event.key === "ArrowRight") {
      nextSlide();
      return;
    }
    if(event.key === "ArrowLeft") {
      previousSlide();
      return;
    }
  },
  false,
);

nextSlide();