z-Index hoe werkt dat?

<script> 
    /***********************************************
* Ultimate Fade-In Slideshow (v1.51):  Dynamic Drive (http://www.dynamicdrive.com)
* This notice MUST stay intact for legal use
* Visit http://www.dynamicdrive.com/ for this script and 100s more.
***********************************************/
 var fadeimages=new Array()
 //SET IMAGE PATHS. Extend or contract array as needed
fadeimages[0]=["http://www.habbotjes.be/topstory/generator.php?topstory=http://www.habbotjes.be/uploads/promo_chatting.gif", "<table width=85% height=210px cellpadding=0 cellspacing=0><tr><td valign=top><div class=kop style=font-family: Verdana; color: #FFFFFF; padding-top: 8px; padding-left: 6px;    font-size: 18px; font-weight: bold;><br /><a href=?p=nieuws&nid=1753 class=wit_muisover>Versie 4 online</a></div><br /> <div class=tussentext style=font-family: Verdana;color: #FFFFFF;padding-left: 6px;font-size: 13px;>Check het bericht om te zien wat er veranderd is!</div></td></tr><tr><td valign=bottom style=padding-bottom:4px; padding-left:4px;><a href=?p=nieuws&nid=1753 class=wit_muisover>Lees meer &raquo;</a></td></tr></table>", ""] //plain image syntax
fadeimages[1]=["http://www.habbotjes.be/topstory/generator.php?topstory=http://www.habbotjes.be/uploads/promo_frontPage_steampunk3.gif", "<table width=85% height=210px cellpadding=0 cellspacing=0><tr><td valign=top><div class=kop style=font-family: Verdana; color: #FFFFFF; padding-top: 8px; padding-left: 6px;    font-size: 18px; font-weight: bold;><br /><a href=?p=nieuws&nid=1741 class=wit_muisover>Donnie Santini heeft je hulp nodig!</a></div><br /> <div class=tussentext style=font-family: Verdana;color: #FFFFFF;padding-left: 6px;font-size: 13px;>Maar waarmee? Lees snel meer!</div></td></tr><tr><td valign=bottom style=padding-bottom:4px; padding-left:4px;><a href=?p=nieuws&nid=1741 class=wit_muisover>Lees meer &raquo;</a></td></tr></table>", ""] //plain image syntax
 
 
 
 
 
/***********************************************
* Settings for Topstory
***********************************************/
var imageheight = "300"
var imagewidth =  "759"
var fadebgcolor= ""
 
/***********************************************
* End settings for Topstory
***********************************************/
 
 
 
////NO need to edit beyond here/////////////
 
var fadearray=new Array() //array to cache fadeshow instances
var fadeclear=new Array() //array to cache corresponding clearinterval pointers
 
var dom=(document.getElementById) //modern dom browsers
var iebrowser=document.all
 
function fadeshow(theimages, fadewidth, fadeheight, borderwidth, delay, pause, displayorder){
this.pausecheck=pause
this.mouseovercheck=0
this.delay=delay
this.degree=10 //initial opacity degree (10%)
this.curimageindex=0
this.nextimageindex=1
fadearray[fadearray.length]=this
this.slideshowid=fadearray.length-1
this.canvasbase="canvas"+this.slideshowid
this.curcanvas=this.canvasbase+"_0"
if (typeof displayorder!="undefined")
theimages.sort(function() {return 0.5 - Math.random();}) //thanks to Mike (aka Mwinter) :)
this.theimages=theimages
this.imageborder=parseInt(borderwidth)
this.postimages=new Array() //preload images
for (p=0;p<theimages.length;p++){
this.postimages[p]=new Image()
this.postimages[p].src=theimages[p][0]
}
 
var fadewidth=fadewidth+this.imageborder*2
var fadeheight=fadeheight+this.imageborder*2
 
if (iebrowser&&dom||dom) //if IE5+ or modern browsers (ie: Firefox)
document.write(<div id="master+this.slideshowid+" style="position:relative;width:+fadewidth+px;height:+fadeheight+px;overflow:hidden;"><div id="+this.canvasbase+_0" style="position:absolute;width:+fadewidth+px;height:+fadeheight+px;top:0;left:0;filter:progid:DXImageTransform.Microsoft.alpha(opacity=10);opacity:0.1;-moz-opacity:0.1;-khtml-opacity:0.1;background-color:+fadebgcolor+"></div><div id="+this.canvasbase+_1" style="position:absolute;width:+fadewidth+px;height:+fadeheight+px;top:0;left:0;filter:progid:DXImageTransform.Microsoft.alpha(opacity=10);opacity:0.1;-moz-opacity:0.1;-khtml-opacity:0.1;background-color:+fadebgcolor+"></div></div>)
else
document.write(<div><img name="defaultslide+this.slideshowid+" src="+this.postimages[0].src+"></div>)
 
if (iebrowser&&dom||dom) //if IE5+ or modern browsers such as Firefox
this.startit()
else{
this.curimageindex++
setInterval("fadearray["+this.slideshowid+"].rotateimage()", this.delay)
}
}
 
function fadepic(obj){
if (obj.degree<100){
obj.degree+=10
if (obj.tempobj.filters&&obj.tempobj.filters[0]){
if (typeof obj.tempobj.filters[0].opacity=="number") //if IE6+
obj.tempobj.filters[0].opacity=obj.degree
else //else if IE5.5-
obj.tempobj.style.filter="alpha(opacity="+obj.degree+")"
}
else if (obj.tempobj.style.MozOpacity)
obj.tempobj.style.MozOpacity=obj.degree/101
else if (obj.tempobj.style.KhtmlOpacity)
obj.tempobj.style.KhtmlOpacity=obj.degree/100
else if (obj.tempobj.style.opacity&&!obj.tempobj.filters)
obj.tempobj.style.opacity=obj.degree/101
}
else{
clearInterval(fadeclear[obj.slideshowid])
obj.nextcanvas=(obj.curcanvas==obj.canvasbase+"_0")? obj.canvasbase+"_0" : obj.canvasbase+"_1"
obj.tempobj=iebrowser? iebrowser[obj.nextcanvas] : document.getElementById(obj.nextcanvas)
obj.populateslide(obj.tempobj, obj.nextimageindex)
obj.nextimageindex=(obj.nextimageindex<obj.postimages.length-1)? obj.nextimageindex+1 : 0
setTimeout("fadearray["+obj.slideshowid+"].rotateimage()", obj.delay)
}
}
 
fadeshow.prototype.populateslide=function(picobj, picindex){
var slideHTML=""
 
if (this.theimages[picindex][1]!="") //if associated link exists for image
slideHTML+=<div style="padding-left: 1px; background-image: url(+this.postimages[picindex].src+); background-position:-3px; height: +imageheight+px; width: +imagewidth+px" border="+this.imageborder+px">+this.theimages[picindex][1]+ <br />
if (this.theimages[picindex][1]!="") //if associated link exists for image
slideHTML+=</a>
picobj.innerHTML=slideHTML
}
 
 
fadeshow.prototype.rotateimage=function(){
if (this.pausecheck==1) //if pause onMouseover enabled, cache object
var cacheobj=this
if (this.mouseovercheck==1)
setTimeout(function(){cacheobj.rotateimage()}, 100)
else if (iebrowser&&dom||dom){
this.resetit()
var crossobj=this.tempobj=iebrowser? iebrowser[this.curcanvas] : document.getElementById(this.curcanvas)
crossobj.style.zIndex++
fadeclear[this.slideshowid]=setInterval("fadepic(fadearray["+this.slideshowid+"])",50)
this.curcanvas=(this.curcanvas==this.canvasbase+"_0")? this.canvasbase+"_1" : this.canvasbase+"_0"
}
else{
var ns4imgobj=document.images[defaultslide+this.slideshowid]
ns4imgobj.src=this.postimages[this.curimageindex].src
}
this.curimageindex=(this.curimageindex<this.postimages.length-1)? this.curimageindex+1 : 0
}
 
fadeshow.prototype.resetit=function(){
this.degree=10
var crossobj=iebrowser? iebrowser[this.curcanvas] : document.getElementById(this.curcanvas)
if (crossobj.filters&&crossobj.filters[0]){
if (typeof crossobj.filters[0].opacity=="number") //if IE6+
crossobj.filters(0).opacity=this.degree
else //else if IE5.5-
crossobj.style.filter="alpha(opacity="+this.degree+")"
}
else if (crossobj.style.MozOpacity)
crossobj.style.MozOpacity=this.degree/101
else if (crossobj.style.KhtmlOpacity)
crossobj.style.KhtmlOpacity=this.degree/100
else if (crossobj.style.opacity&&!crossobj.filters)
crossobj.style.opacity=this.degree/101
}
 
 
fadeshow.prototype.startit=function(){
var crossobj=iebrowser? iebrowser[this.curcanvas] : document.getElementById(this.curcanvas)
this.populateslide(crossobj, this.curimageindex)
if (this.pausecheck==1){ //IF SLIDESHOW SHOULD PAUSE ONMOUSEOVER
var cacheobj=this
var crossobjcontainer=iebrowser? iebrowser["master"+this.slideshowid] : document.getElementById("master"+this.slideshowid)
crossobjcontainer.onmouseover=function(){cacheobj.mouseovercheck=1}
crossobjcontainer.onmouseout=function(){cacheobj.mouseovercheck=0}
}
this.rotateimage()
} 
</script>

function Browser() {

  var ua, s, i;

  this.isIE    = false;
  this.isNS    = false;
  this.version = null;

  ua = navigator.userAgent;

  s = "MSIE";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isIE = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  s = "Netscape6/";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  // Treat any other "Gecko" browser as NS 6.1.

  s = "Gecko";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = 6.1;
    return;
  }
}

var browser = new Browser();

// Global object to hold drag information.

var dragObj = new Object();
dragObj.zIndex = 20

function dragStart(event, id) {

  var el;
  var x, y;

  // If an element id was given, find it. Otherwise use the element being
  // clicked on.

  if (id)
    dragObj.elNode = document.getElementById(id);
  else {
    if (browser.isIE)
      dragObj.elNode = window.event.srcElement;
    if (browser.isNS)
      dragObj.elNode = event.target;

    // If this is a text node, use its parent element.

    if (dragObj.elNode.nodeType == 3)
      dragObj.elNode = dragObj.elNode.parentNode;
  }

  // Get cursor position with respect to the page.

  if (browser.isIE) {
    x = window.event.clientX + document.documentElement.scrollLeft
      + document.body.scrollLeft;
    y = window.event.clientY + document.documentElement.scrollTop
      + document.body.scrollTop;
  }
  if (browser.isNS) {
    x = event.clientX + window.scrollX;
    y = event.clientY + window.scrollY;
  }

  // Save starting positions of cursor and element.

  dragObj.cursorStartX = x;
  dragObj.cursorStartY = y;
  dragObj.elStartLeft  = parseInt(dragObj.elNode.style.left, 10);
  dragObj.elStartTop   = parseInt(dragObj.elNode.style.top,  10);

  if (isNaN(dragObj.elStartLeft)) dragObj.elStartLeft = 0;
  if (isNaN(dragObj.elStartTop))  dragObj.elStartTop  = 0;

  // Update elements z-index.

  dragObj.elNode.style.zIndex = ++dragObj.zIndex;

  // Capture mousemove and mouseup events on the page.

  if (browser.isIE) {
    document.attachEvent("onmousemove", dragGo);
    document.attachEvent("onmouseup",   dragStop);
    window.event.cancelBubble = true;
    window.event.returnValue = false;
  }
  if (browser.isNS) {
    document.addEventListener("mousemove", dragGo,   true);
    document.addEventListener("mouseup",   dragStop, true);

    event.preventDefault();
  }
}

function dragGo(event) {

  var x, y;

  // Get cursor position with respect to the page.

  if (browser.isIE) {
    x = window.event.clientX + document.documentElement.scrollLeft
      + document.body.scrollLeft;
    y = window.event.clientY + document.documentElement.scrollTop
      + document.body.scrollTop;
  }
  if (browser.isNS) {
    x = event.clientX + window.scrollX;
    y = event.clientY + window.scrollY;
  }

  // Move drag element by the same amount the cursor has moved.

  dragObj.elNode.style.left = (dragObj.elStartLeft + x - dragObj.cursorStartX) + "px";
  dragObj.elNode.style.top  = (dragObj.elStartTop  + y - dragObj.cursorStartY) + "px";

  if (browser.isIE) {
    window.event.cancelBubble = true;
    window.event.returnValue = false;
  }
  if (browser.isNS)
    event.preventDefault();
}

function dragStop(event) {

  // Stop capturing mousemove and mouseup events.

  if (browser.isIE) {
    document.detachEvent("onmousemove", dragGo);
    document.detachEvent("onmouseup",   dragStop);
  }
  if (browser.isNS) {
    document.removeEventListener("mousemove", dragGo,   true);
    document.removeEventListener("mouseup",   dragStop, true);
  }
}

function dragHidden(id, clase) {
    if(document.getElementById(id).className == "hidden"){
    document.getElementById(id).className = clase;
    document.getElementById(aktie_+id).innerHTML = "sluit";
    }else{
    document.getElementById(id).className = "hidden";
    document.getElementById(aktie_+id).innerHTML = "open";
    }
}

function openDiv(id) {
    var x = document.getElementById(id);
    if(x.style.display == "block") {
        x.style.display = "none";
    }else{
        x.style.display = "block";
    }
}
function sluitDiv(id) {
    var x = document.getElementById(id);
    x.style.display = "none";
}