function getPageScroll(){

	if (self.pageYOffset) {
		yScroll = self.pageYOffset;
		xScroll = self.pageXOffset;
	} else if (document.documentElement && document.documentElement.scrollTop){	 // Explorer 6 Strict
		yScroll = document.documentElement.scrollTop;
		xScroll = document.documentElement.scrollLeft;
	} else if (document.body) {// all other Explorers
		yScroll = document.body.scrollTop;
		xScroll = document.body.scrollLeft;	
	}

	arrayPageScroll = new Array(xScroll,yScroll);
	return arrayPageScroll;
}

function moveLayer(oLayer,width,height,versatz){

	var pageXOffset = getPageScroll()[0];
	var pageYOffset = getPageScroll()[1];
	
	var left = (screen.availWidth - width) / 2;
	var top = ((versatz) ? versatz : 0) + pageYOffset;
	
	oLayer.style.left = left + 'px';
	oLayer.style.top = top + 'px';

}

function showLayer(oLayer,anzeige){
	if(anzeige){
		oLayer.style.visibility = 'visible';
		oLayer.style.display = 'block';	
	}
	else{
		oLayer.style.visibility = 'hidden';
		oLayer.style.display = 'none';	
	}
}

function setInfoLayerActiv(set_width,set_height){

	var pageXOffset = getPageScroll()[0];
	var pageYOffset = getPageScroll()[1];

	var oLayer = document.getElementById('BackgroundLayer');
	var top = pageYOffset;
	oLayer.style.top = top + 'px';
	
	showLayer(oLayer,true);
	
	oLayer = document.getElementById('BannerLayer');	
	var width = (set_width) ? set_width : 640;
	var height = (set_height) ? set_height : 480;
		
	moveLayer(oLayer,width,height,50);	
		
	oLayer.style.width = width + 'px';
	oLayer.style.height = height + 'px';
	
	showLayer(oLayer,true);
	
}

function setInfoLayerInActiv(){
	showLayer(document.getElementById('BackgroundLayer'),false);	
	showLayer(document.getElementById('BannerLayer'),false);
}