var curImg = 0;
var timerId = -1;
var intervalf = 3000;
var intervalm = 4500;
var intervals = 6000;
var interval = intervalm;
var isPlaying = 1;

function replaceNum()
{
  var input = SHOWINGSTRING;
  var output = input;
  var idx = output.indexOf("%slideNum");
  if (idx > -1) {
    output = input.substring(0, idx);
    output += eval(curImg+1);
    output += input.substr(idx+9);
  }
  return output;
}

function changeSpeed()
{
  var sidx = document.forms[0].speedMenu.selectedIndex;
  if (sidx == 0) {
    interval = intervals;
  } else if (sidx == 1) {
    interval = intervalm;
  } else {
    interval = intervalf;
  }

  if (timerId != -1) {
    clearTimers();
  }

  play();
}

function imgLoadNotify()
{
  if (isPlaying == 1)
    setTimers();
}

function changeSlide()
{

  if (timerId != -1) {
    clearTimers();
  }

    var html = "<img src=" + imageSrcArray[curImg] + " alt=\"photo\"" +
      " border=1 onload=\"imgLoadNotify();\"><P>";

  var pnumLine = "<font face=arial size=1>";
  pnumLine += replaceNum();
  pnumLine += "</font>";

    var htmlDesc = "<span class=\"hls\">" + imageTitleArray[curImg] + "</span>";
    htmlDesc += "<br>" + imageDescArray[curImg];

    var htmlDate = imageDateArray[curImg];
    var htmlCpyright = imageProviderArray[curImg];

  switch(navigator.family) {
    case 'gecko':
      document.getElementById("imgDiv").innerHTML = html;
      document.getElementById("pnumDiv").innerHTML = pnumLine;
      document.getElementById("descDiv").innerHTML = htmlDesc;
      document.getElementById("dateDiv").innerHTML = htmlDate;
      document.getElementById("cpyrightDiv").innerHTML = htmlCpyright;
      break;
    case 'nn4':
      document.layers[1].document.imgDiv.document.open();
      document.layers[1].document.imgDiv.document.write(html);
      document.layers[1].document.imgDiv.document.close();

      document.layers[0].document.pnumDiv.document.open();
      document.layers[0].document.pnumDiv.document.write(pnumLine);
      document.layers[0].document.pnumDiv.document.close();

      document.layers[2].document.descDiv.document.open();
      document.layers[2].document.descDiv.document.write(htmlDesc);
      document.layers[2].document.descDiv.document.close();

      document.layers[3].document.dateDiv.document.open();
      document.layers[3].document.dateDiv.document.write(htmlDate);
      document.layers[3].document.dateDiv.document.close();

      document.layers[4].document.cpyrightDiv.document.open();
      document.layers[4].document.cpyrightDiv.document.write(htmlCpyright);
      document.layers[4].document.cpyrightDiv.document.close();
      break;
    case 'ie4':
      document.all.pem.innerHTML = pnumLine;
      document.all.imgp.innerHTML = html;
      document.all.desctxt.innerHTML = htmlDesc;
      document.all.datetxt.innerHTML = htmlDate;
      document.all.cpyrighttxt.innerHTML = htmlCpyright;
      break;
  }
}

function forward()
{
  curImg++;
  if (curImg == numImgs)
    curImg = 0;
  changeSlide();
}

function rewind()
{
  curImg--;
  if (curImg < 0)
      curImg = numImgs - 1;
  changeSlide();
}

function stop()
{
  clearTimers();

  isPlaying = 0;

  document.playbtn.src = buttonImgPfx + buttonOffArray[0];
  document.stopbtn.src = buttonImgPfx + buttonOnArray[1];
}

function play()
{
  setTimers();
  startShow();
}

function startShow()
{
  isPlaying = 1;

  document.playbtn.src = buttonImgPfx + buttonOnArray[0];
  document.stopbtn.src = buttonImgPfx + buttonOffArray[1];
}

function setTimers()
{
  if (timerId == -1)
    timerId = window.setInterval('forward();', interval);
}

function clearTimers()
{
  window.clearInterval(timerId);
  timerId = -1;
}

function setButton(direction)
{
  if (direction == 0) {
    document.prevbtn.src = buttonImgPfx + buttonOnArray[2];
    window.setTimeout("document.prevbtn.src = buttonImgPfx + buttonOffArray[2];", 300);
  } else {
    document.fowdbtn.src = buttonImgPfx + buttonOnArray[3];
    window.setTimeout("document.fowdbtn.src = buttonImgPfx + buttonOffArray[3];", 300);
  }
}