/* Image cross fader (C)2004 Patrick H. Lauke */

var galleryId = 'gallery';
var  gallery;
var galleryImages;
var currentImage;
var previousImage;
var preInitTimer;
preInit();

/* functions */

function preInit() {
  if ((document.getElementById)&&(gallery=document.getElementById(galleryId))) {
    gallery.style.visibility = "hidden";
    if (typeof preInitTimer != 'undefined') clearTimeout(preInitTimer);
  } else {
    preInitTimer = setTimeout("preInit()",2);
  }
}

function fader(imageNumber,opacity) {
  /* helper function to deal specifically with images and the cross-browser differences in opacity handling */
  var obj=galleryImages[imageNumber];
  if (obj.style) {
    if (obj.style.MozOpacity!=null) {
      /* Mozilla's pre-CSS3 proprietary rule */
      obj.style.MozOpacity = (opacity/100) - .001;
    } else if (obj.style.opacity!=null) {
      /* CSS3 compatible */
      obj.style.opacity = (opacity/100) - .001;
    } else if (obj.style.filter!=null) {
      /* IE's proprietary filter */
      obj.style.filter = "alpha(opacity="+opacity+")";
    }
  }
}

function fadeInit() {
  if (document.getElementById) {
    preInit();
    galleryImages = new Array;
    var node = gallery.firstChild;
    while (node) {
      if (node.nodeType==1) {
        galleryImages.push(node);
      }
      node = node.nextSibling;
    }
    for(i=0;i<galleryImages.length;i++) {
      /* loop through all these child nodes and set up their styles */
      galleryImages[i].style.position='absolute';
      galleryImages[i].style.top=0;
      galleryImages[i].style.zIndex=0;
      /* set their opacity to transparent */
      fader(i,0);
    }
    /* make the list visible again */
    gallery.style.visibility = 'visible';
    /* initialise a few parameters to get the cycle going */
    currentImage=0;
    previousImage=galleryImages.length-1;
    opacity=100;
    fader(currentImage,100);
    /* start the whole crossfade process after a second's pause */
    window.setTimeout("crossfade(100)",1000);
  }
}

function crossfade(opacity) {
    if (opacity < 100) {
      /* current image not faded up fully yet...so increase its opacity */
      fader(currentImage,opacity);
      /* fader(previousImage,100-opacity); */
      opacity += 10;
      window.setTimeout("crossfade("+opacity+")", 30);
    } else {
      /* make the previous image - which is now covered by the current one fully - transparent */
      fader(previousImage,0);
      /* current image is now previous image, as we advance in the list of images */
      previousImage=currentImage;
      currentImage+=1;
      if (currentImage>=galleryImages.length) {
        /* start over from first image if we cycled through all images in the list */
        currentImage=0;
      }
      /* make sure the current image is on top of the previous one */
      galleryImages[previousImage].style.zIndex = 0;
      galleryImages[currentImage].style.zIndex = 1;
      /* and start the crossfade after a second's pause */
      opacity=0;
      window.setTimeout("crossfade("+opacity+")", 6000);
    }

}

/* initialise fader by hiding image object first */
addEvent(window,'load',fadeInit)



/* 3rd party helper functions */

/* addEvent handler for IE and other browsers */
function addEvent(elm, evType, fn, useCapture)
{
 if (elm.addEventListener){
   elm.addEventListener(evType, fn, useCapture);
   return true;
 } else if (elm.attachEvent){
   var r = elm.attachEvent("on"+evType, fn);
   return r;
 }
}