var index = 0;

function goSlide(n) {
  index += n;
  showSlide();
}

function pSlide(n) {
  index = n;
  showSlide();
}

function showSlide() {
  var i;
  var slides = document.getElementsByClassName("pslide");
//  var thumbs = document.getElementsByClassName("pthumb");
  if (index >= slides.length) {index = 0}    
  if (index < 0) {index = slides.length - 1}
  for (i = 0; i < slides.length; i++)
  {
    slides[i].style.display = "none";
//    thumbs[i].className = thumbs[i].className.replace(" active", "");
  }
  slides[index].style.display = "block";
//  thumbs[index].className += " active";

  document.getElementById("pn").innerHTML = (index + 1) + " / " + slides.length;
}

function autoSlide() {
  showSlide();
  index++;
  setTimeout(autoSlide, 5000);
}