//--- Browser Version ---
function browserversion()
	{
	return parseInt(navigator.appVersion);
	}

//--- Internet Explorer ---
function explorer()
	{
	if(navigator.appName.indexOf("Microsoft") != -1)
		return true;
	return false;
	}

//--- Netscape ---
function netscape()
	{
	if(navigator.appName.indexOf("Netscape") != -1)
		return true;
	return false;
	}

//--- Macintosh ---
function macintosh()
	{
	if(navigator.userAgent.indexOf("Mac") != -1)
		return true;
	return false;
	}

//--- Layer Support pruefen ---
function layersupport()
	{
	if((explorer()) && (browserversion() >= 4) && (document.all))
		return true;

	if((netscape()) && (browserversion() >= 4) && (document.layers))
		return true;

	return false;
	}