var currentFrame = "home";
var currentpic = 1;

//when adding new pictures to the virtual tour
//set this value to the number of pictures available.
var totalpics = 3;

function update(page) {
   if (page != currentFrame) {
      var new_page = document.getElementById(page);
      var current_page = document.getElementById(currentFrame);
      var new_tab = document.getElementsByName(page + '_tab');
      var old_tab = document.getElementsByName(currentFrame + '_tab');
      current_page.style.display = "none";
      new_page.style.display = "";
      for (var i = 0; i < new_tab.length; i++) {
         new_tab[i].style.backgroundColor="#CC9966";
      }
      for (var i = 0; i < old_tab.length; i++) {
         old_tab[i].style.backgroundColor="#FFCC99";
      }
      currentFrame = page;
   }
}

function showpic() {
   var tour_image = document.getElementById("tour_image");

   //images in the tour are saved in the images/tour directory and 
   //have the names 1.jpg, 2.jpg, 3.jpg etc. depending on what order
   //they are to be shown in.
   tour_image.src = "images/tour/" + currentpic + ".jpg";

   var caption = document.getElementById("caption");
   caption.firstChild.firstChild.data = currentpic + '/' + totalpics;
   var prev_link = document.getElementById("prev_link");
   var next_link = document.getElementById("next_link");
   if (currentpic == 1) {
      prev_link.firstChild.firstChild.data = "";
      next_link.firstChild.firstChild.data = ">>";
   } else if (currentpic == totalpics) {
      next_link.firstChild.firstChild.data = "";
      prev_link.firstChild.firstChild.data = "<<";
   } else {
       prev_link.firstChild.firstChild.data = "<<";
       next_link.firstChild.firstChild.data = ">>";
   }
}

function prevpic() {
   if (currentpic > 1) {
      currentpic = currentpic - 1;
      showpic();
   }
}

function nextpic() {
   if (currentpic < totalpics) {
      currentpic = currentpic + 1;
      showpic();
   }
}