var visibleSlide;
var timer;

function displayPreviousSlideAndStop()
{
	displayPreviousSlide();
	stopSlide();
}

function displayNextSlideAndStop()
{
	displayNextSlide();
	stopSlide();
}

function displaySlideAndStop(slide)
{
	displaySlide(slide);
	stopSlide();
}

function displaySlide(slide)
{
  document.getElementById('slide1').style.display = 'none';
  document.getElementById('slide2').style.display = 'none';
  document.getElementById('slide3').style.display = 'none';

  document.getElementById('slide1').style.visibility = 'hidden';
  document.getElementById('slide2').style.visibility = 'hidden';
  document.getElementById('slide3').style.visibility = 'hidden';

  document.getElementById('link_slide1').className = 'toc';
  document.getElementById('link_slide2').className = 'toc';
  document.getElementById('link_slide3').className = 'toc';

  document.getElementById('slide'+slide).style.display = 'block';
  document.getElementById('slide'+slide).style.visibility = 'visible';
  document.getElementById('link_slide'+slide).className = 'toc selected';

  visibleSlide = slide;
}

function displayPreviousSlide()
{
  if ( visibleSlide == 1 )
    displaySlide(3);
  else
    displaySlide(visibleSlide-1);
}

function displayNextSlide()
{
  if ( visibleSlide == 3 )
    displaySlide(1);
  else
    displaySlide(visibleSlide+1);
}

function startSlide()
{
  displayNextSlide();
  timer = setTimeout("startSlide()",4000);
}

function stopSlide()
{
  clearTimeout(timer);
}