var browserName = navigator.appName; var browserVersion = parseFloat(navigator.appVersion);
var showDom=null; var hideDom=null; var dom=null; oldId='intro'; var clipID=null;
var layerName='submuseum'; var subLayerName='submuseumtentoonstellingen'; var hide=true;
var oldLayerName=layerName; var clipHeight='300';

var mac_ie4=false;

if (navigator.userAgent && (navigator.userAgent.indexOf("Mac") >= 0) && (browserName == "Microsoft Internet Explorer") && (browserVersion >= 4.0) && (navigator.appVersion.indexOf('MSIE 4') != -1))
	mac_ie4=true;

function showLayer(id)
{
	if (id != 'subsluit')
		subLayerName=id;
		
	showDom=styleRef(id);
	showDom.visibility='visible';
}

function showSubMenu(id)
{
	showLayer(id);
}


function hideLayer(id)
{
	hideDom=styleRef(id);
	hideDom.visibility='hidden';
}


function hideMenu(id)
{
	hideDom=styleRef(id);
	hideDom.visibility='hidden';
}

function hideSubMenus()
{
	hideLayer(subLayerName);
}

function hideAllMenus()
{
	hideMenu(layerName);
	hideSubMenus();
}

function clipMenu(newLayer)
{
	oldLayerName=layerName; layerName=newLayer;
	oldDom=styleRef(oldLayerName); dom=styleRef(layerName); hideSubMenus();
	
	if (dom.visibility == 'visible' || dom.visibility == 'show' || clipID != null)
	{	oldDom.visibility='hidden'; dom.visibility='hidden';}
	else
	{
		hideMenu(oldLayerName);
		dom.visibility='visible'; clipHeight=getLayerHeight(newLayer);
		visibleHeight=0;
		
		if (clipID != null)
			clearTimeout(clipID);
			
		clipIt()
	}
}

function clipIt()
{	
	visibleHeight+=30;
	
	if (visibleHeight <= clipHeight)
	{	
		if (document.all)
		{
			dom.clip='rect(0px, 165px, ' + visibleHeight + 'px, ' + 0 + 'px)';	
			
			if (mac_ie4) dom.pixelHeight=visibleHeight;
		}
		if (document.layers)
		{
			dom.clip.top = 0; 
			dom.clip.bottom = visibleHeight;	
		}
		if (document.getElementById)
		{
			dom.clip='rect(0px, 165px, ' + visibleHeight + 'px, ' + 0 + 'px)';	
		}

		clipID=setTimeout('clipIt()',5);
	}
	else
	{
		clearTimeout(clipID); clipID=null;
	}
}