var numSlides = 0;
var currentSlide = 0;

$(document).ready(function() {
    $(document).keyup(handleKeys);
    numSlides = $("div.slide").css("display", "none").click(nextSlide).each(function (i) {
        $(this).attr("id", "slide_" + i);
      }).size();
    showSlide();
  });




function handleKeys(e) {
  var keyID = (window.event) ? event.keyCode : e.keyCode;

  switch(keyID) {
    case 32:
      nextSlide();
      break;
    case 37:
      prevSlide();
      break;
    case 38:
      setSlide(0);
      break;
    case 39:
      nextSlide();
      break;
    case 40:
      lastSlide();
      break;
  }
}


function showSlide() {
  $("div.slide").css("display", "none");

  $("#slide_" + currentSlide).css("display", "inline");
}

function setSlide(number) {
  currentSlide = number;
  showSlide();
}


function nextSlide() {
  currentSlide++;
  if (currentSlide >= numSlides) {
    currentSlide = 0;
  }

  showSlide();
}

function prevSlide() {
  currentSlide--;
  if (currentSlide < 0) {
    currentSlide = 0;
  }

  showSlide();
}

function lastSlide() {
  currentSlide = (numSlides - 1);
  showSlide();
}