var isDHTML = 0;
var isLayers = 0;
var isAll = 0;
var isID = 0;

if (document.getElementById) {isID = 1; isDHTML = 1;}
else {
if (document.all) {isAll = 1; isDHTML = 1;}
else {
browserVersion = parseInt(navigator.appVersion);
if ((navigator.appName.indexOf('Netscape') != -1) && (browserVersion == 4)) {isLayers = 1; isDHTML = 1;}
}}

function findDOMFrame(objectID,frameName,withStyle) 
{
 	if (document.getElementById) 
	{
		 isID = 1; isDHTML = 1;
	}
	else 
	{
		if (document.layers) 
		{
		 	isLayers = 1; isDHTML = 1;
		}
		else 
		{
			if (document.all) 
			{
			 	 isAll = 1; isDHTML = 1;
			}
		}
	}
		
	if (withStyle == 1) {
		if (isID) { return (top [frameName].document.getElementById(objectID).style) ; }
		else { 
			if (isAll) { return (top [frameName].document.all[objectID].style); }
		else {
			if (isLayers) {  return (top [frameName].document.layers[objectID]); }
		};}
	}
	else {
		if (isID) { return (top [frameName].document.getElementById(objectID)) ; }
		else { 
			if (isAll) { return (top [frameName].document.all[objectID]); }
		else {
			if (isLayers) { return (top [frameName].document.layers[objectID]); }
		};}
	}
}

function hideSubmenus()
{
	 style1=findDOMFrame('Einf_submenu','Navigation',1);
	 if(style1)
	 {
	 	 style1.display = "none";
	 }
	 style1=findDOMFrame('Biblio_submenu','Navigation',1);
	 if(style1)
	 {
	 	 style1.display = "none";
	 }
	 style1=findDOMFrame('artikel_submenu','Navigation',1);
	 if(style1)
	 {
	 	 style1.display = "none";
	 }
	 style1=findDOMFrame('rezensionen_submenu','Navigation',1);
	 if(style1)
	 {
	 	 style1.display = "none";
	 }
}

function showLayer(layerId)
{
	 style1=findDOMFrame(layerId,'Navigation',1);
	 if(style1)
	 {
	 	 style1.display = "block";
	 }
}

function updateMenu(SubMenu)
{
    hideSubmenus();
		if(SubMenu)		 					/*wenn SubMenu == 0 ist, werden alle Submenus versteckt*/
		{
		 	showLayer(SubMenu);
		}

		frame='nav';
	 style1=findDOMFrame(frame,'Hauptfenster',1);
	 if(style1)
	 {
	 	 style1.display = "none";
	 }
}