var numberOfPages=0;
var numberOfImages=0;
var numberVisible=4;
var currentImage=1;

var nextImgActive=new Image();
var nextImgInactive=new Image();
var prevImgActive=new Image();
var prevImgInactive=new Image();

var allImages=new Array(numberOfPages*numberVisible);
var allAnchors=new Array(numberOfPages*numberVisible);


function init(basename,numPage,numImg)
{
  numberOfPages=numPage;
  numberOfImages=numImg;

  if (document.images) 
  {
    for (i=1; i<=numberOfImages; i++)
    {
      allImages[i-1] = new Image();
      allImages[i-1].src="images/"+basename+"_th"+i+".jpg";

      allAnchors[i-1] = new String(basename+i+".html");
    }
  }

  if (numberOfPages == 1)
  {
    disableLink(document.links[14]);
  }
  disableLink(document.links[13]);

  nextImgActive.src="images/next_blue.gif";
  nextImgInactive.src="images/next_grey.gif";
  prevImgActive.src="images/previous_blue.gif";
  prevImgInactive.src="images/previous_grey.gif";

  if (numberOfImages <= numberVisible)
  {
    document.images["nextImg"].src=nextImgInactive.src;
  }
}

function openpopup(popurl)
{
  if (popurl)
  {
  	winpops=window.open(popurl,"","width=395, height=410,");
  }
}

function next()
{
  var startingImage=1;
  if ( (currentImage+(2*numberVisible)-1) > (numberOfPages*numberVisible))
  {
    return;
  }
  else if ( (currentImage+(2*numberVisible)-1) == (numberOfPages*numberVisible))
  {
    startingImage=currentImage+numberVisible;
    disableLink(document.links[14]);
    document.images["nextImg"].src=nextImgInactive.src;
    enableLink(document.links[13]);
    document.images["prevImg"].src=prevImgActive.src;
  }
  else
  {
    startingImage=currentImage+numberVisible;
    enableLink(document.links[13]);
    document.images["prevImg"].src=prevImgActive.src;
  }

  for (i=0; i<numberVisible; i++)
  {
    var j=eval(i+1);
    var k=numberOfImages+1-startingImage;
    if (i<k)
    {
      document.images[new String("img"+j)].src=allImages[startingImage+i-1].src;
    }
    else
    {
      document.images[new String("img"+j)].src="images/spacer.gif";
    }
  }
  currentImage=startingImage;
}

function prev()
{
  var startingImage=1;
  if ( (currentImage-numberVisible) < 1)
  { 
    return;
  }
  else if ( (currentImage-numberVisible) == 1)
  {
    startingImage=currentImage-numberVisible;
    disableLink(document.links[13]);
    document.images["prevImg"].src=prevImgInactive.src;
    enableLink(document.links[14]);
    document.images["nextImg"].src=nextImgActive.src;
  }
  else
  {
    startingImage=currentImage-numberVisible;
    enableLink(document.links[14]);
    document.images["nextImg"].src=nextImgActive.src;
  }

  for (i=0; i<numberVisible; i++)
  {
    var j=eval(i+1);
    document.images[new String("img"+j)].src=allImages[startingImage+i-1].src;
  }
  currentImage=startingImage;
}

function cancelLink () {
  return false;
}

function disableLink (link) {
  if (link.onclick)
    link.oldOnClick = link.onclick;
  link.onclick = cancelLink;
  if (link.style)
    link.style.cursor = 'default';
}

function enableLink (link) {
  link.onclick = link.oldOnClick ? link.oldOnClick : null;
  if (link.style)
    link.style.cursor = 
      document.all ? 'hand' : 'pointer';
}

function toggleLink (link) {
  if (link.disabled) 
    enableLink (link)
  else 
    disableLink (link);
  link.disabled = !link.disabled;
}