// Browser erkennen
function autoslide(){
	if (window.switchSlide) {
		auto_slide = window.setInterval("switchSlide('forward',' ');", 3800);
	}
}

var InternetExplorer = navigator.appName.indexOf("Microsoft") != -1;

var aktiv = null;
var slideID = 1;
var positiv = 0;
var schrittweite = 5;
var slideLength = 12;
function switchSlide (order,stop_auto){
	if (stop_auto == 'stop_auto') {
		window.clearInterval(auto_slide);
	}
	if (aktiv != null) {
		return;
	}

	oldid = slideID;
	if(order == 'forward'){
		if(slideID == slideLength){
			slideID = 1;
		}else{
			slideID = slideID + 1;
		}
	}else{
		if(slideID == 1){
			slideID = slideLength;
		}else{
			slideID = slideID - 1;
		}
	}
	positiv = 0;

	// Altes Bild in den Hintergrund setzen
	swapForeground(oldid,slideID);
	aktiv = window.setInterval("blend(\"" + oldid + "\",\"" + slideID + "\");", 40);
}

function swapForeground(background,foreground) {
	setStyle(background,1,100);
	setStyle(foreground,2,0);
}

function setStyle(layerid,index,opacity) {
	if (InternetExplorer){
		document.getElementById(layerid).style.zIndex = index;
		document.getElementById(layerid).style.setAttribute('filter', 'alpha(opacity='+opacity+')');
		document.getElementById(layerid).style.setAttribute('display', 'block');
	} else {
		tmp = opacity / 100;
		document.getElementById(layerid).setAttribute('style','display: block; position: absolute; z-index: '+index+';-moz-opacity:'+tmp+';');
	}
}

function blend(oldid, newid) {
	positiv = positiv + schrittweite;
	setStyle(newid,2,positiv);

	// Beim IE wird das Hintergrundbild ausgefadet
	if (InternetExplorer) setStyle(oldid,1,100-(100 / 1000000 * (positiv * positiv * positiv)));	
	
	if (positiv >= 100){
		setStyle(oldid,1,0);
		window.clearInterval(aktiv);
		aktiv=null;
	}
}