// rotatingContent.js
(document.layers) ? layerobject=true : layerobject=false;
(document.all) ? allobject=true : allobject=false;
(document.getElementById) ? dom=true : dom=false;

opera=navigator.userAgent.toLowerCase().indexOf('opera') != -1;

var contentIndex=0;

function getElement(layerName, parentLayer) {
	if (layerobject) {
		parentLayer = (parentLayer) ? parentLayer : self;
		layerCollection = parentLayer.document.layers;
		if (layerCollection[layerName]) 
			return layerCollection[layerName];
		
		for (i=0; i<layerCollection.length;)
			return(getElement(layerName, layerCollection[i++]));
	}
	
	if (allobject)
		return document.all[layerName];
	
	if (dom)
		return document.getElementById(layerName);
}

function hide(layerName) {
	var theLayer = getElement(layerName);
	if (layerobject) 
		theLayer.visibility = 'hide';
	else
		theLayer.style.visibility = 'hidden';
}

function show(layerName) {
	var theLayer = getElement(layerName);
	if (layerobject) 
		theLayer.visibility = 'show';
	else
		theLayer.style.visibility = 'visible';
}

function setZ(layerName, zIndex) {
	var theLayer = getElement(layerName);
	if (layerobject) 
		theLayer.zIndex = zIndex;
	else
		theLayer.style.zIndex = zIndex;
}

function setHeight(layerName, height) {
	var theLayer = getElement(layerName);
	if (layerobject)
		theLayer.clip.height = height;
	else if (opera) 
		theLayer.style.pixelHeight = height;
	else
		theLayer.style.height = height;
}

function setWidth(layerName, width) {
	var theLayer = getElement(layerName);
	if (layerobject) 
		theLayer.clip.width = width;
	else if (opera)
		theLayer.style.pixelWidth = width;
	else 
		theLayer.style.width = width;
}

function raise(layerName) {
	show(layerName);
	setZ(layerName, 2);
}

function lower(layerName) {
	hide(layerName);
	setZ(layerName, 1);
}

function rotate(layerPrefix, length) {
	for (i=0; i<length; i++) {
		if (i == contentIndex) {
			raise(layerPrefix.concat(i))
		} else {
			lower(layerPrefix.concat(i))
		}
	}
	contentIndex++;
	if (contentIndex >= length) contentIndex = 0;
}