// Slide navigation. Requires slides called slideXX.html .

document.addEventListener("keypress", checkKeyPress, true);

// e.preventDefault() stops the keypress being passed to Type Ahead Find.
function checkKeyPress(e) {
   var key = e.which ? e.which : e.keyCode;
   
   switch(key)
   {
     case 33:   // Page Up
     case 37:   // Left Arrow
     case 80:   // P
     case 112:  // p
       prevSlide();
       e.preventDefault();
       break;
       
     case 34:   // Page Down
     case 39:   // right arrow
     case 78:   // N
     case 110:  // n
       nextSlide(); 
       e.preventDefault();
       break;
       
     case 36:   // Home
     case 72:   // H
     case 104:  // h
       window.location="slide00.html";
       e.preventDefault();
       break;
       
     default:        
   }   
}

function nextSlide() {
  var url = new String(window.location);
  var number = url.substr(url.length - 7, 2);
  number++;

  // We use a <span id='last_slide' /> to denote the last slide.
  if (document.getElementById &&
      document.getElementById('last_slide')) { return 0; }

  if (number.toString().length == 1) {
    number = "0" + number.toString();
  }
  window.location="slide" + number + ".html";
}

function prevSlide() {
  var url = new String(window.location);
  var number = url.substr(url.length - 7, 2);

  // Let's not run off the end of the slides
  if (number == 0) { return 0; }
  number--;

  if (number.toString().length == 1) {
    number = "0" + number.toString();
  }

  window.location="slide" + number + ".html";
}