function isBrowserValid(){
	var valid = true;		
	var name = navigator.userAgent.toLowerCase()
	var ie = (name.indexOf("msie") != -1);
	var opera = (name.indexOf("opera") != -1);
	var netscape = (name.indexOf("mozilla")!=-1 && name.indexOf("compatible")==-1);
	var version = navigator.appVersion.toLowerCase();
	var nummer = version.substr(0, version.indexOf("."));
	
	if(opera){
			if (nummer < 6 ){ valid = false; }

	//	valid = false; // we currently (temporarly) do not support opera cause there are problem with the menu
	//	if(nummer<){ valid = false; /* opera6 wird nicht unterstuetzt; menue problem */ }
	}
	else{
		if (netscape){
			if(nummer < 5){ valid = false; /* netscape 4.7 wird nicht unterstuetzt; layer problem */ }
		}
		else{
			if (ie){
				if (nummer < 4 ){ valid = false; }
				if (nummer >= 4 && version.indexOf("msie 5")==-1 && version.indexOf("msie 6")==-1 && version.indexOf("msie 7")==-1 && version.indexOf("msie 8")==-1){ /* IE 4 -> invalid */ valid = false; }
				if (nummer >= 4 && version.indexOf("msie 5")!=-1 && version.indexOf("msie 6")==-1 && version.indexOf("msie 7")==-1 && version.indexOf("msie 8")==-1) { /* perfekt IE 5*/ }
				if (nummer >= 4 && version.indexOf("msie 6")!=-1 && version.indexOf("msie 5")==-1 && version.indexOf("msie 7")==-1 && version.indexOf("msie 8")==-1){ /* perfekt IE 6*/ }
				if (nummer >= 4 && version.indexOf("msie 6")==-1 && version.indexOf("msie 5")==-1 && version.indexOf("msie 7")!=-1 && version.indexOf("msie 8")==-1){ /* perfekt IE 7*/ }
				if (nummer >= 4 && version.indexOf("msie 6")==-1 && version.indexOf("msie 5")==-1 && version.indexOf("msie 7")==-1 && version.indexOf("msie 8")!=-1){ /* perfekt IE 8*/ }
			}
			else{
				/* browser kenn ich nicht was machen? */
			}
		}
	}
	return valid;
}

function getBrowserNickName()
{
	var nickName = "unknown";		
	var name = navigator.userAgent.toLowerCase();
	var ie = (name.indexOf("msie") >= -1);
	var opera = (name.indexOf("opera") != -1);
	var netscape = (name.indexOf("mozilla")!=-1 && name.indexOf("compatible")==-1);
	var version = navigator.appVersion.toLowerCase();
	var nummer = version.substr(0, version.indexOf("."));
	if(opera)
	{
		nickName = "opera"+nummer;
	}
	else
	{
		if (netscape)
		{
			if(nummer < 5)
			{
				nickName = "netscape4";
			}
			else
			{
				nickName = "netscape"+nummer;
			}			
		}
		else
		{
			if (ie)
			{
				nickName = "ie"+nummer;
				if (nummer >= 4 && version.indexOf("msie 5")==-1 && version.indexOf("msie 6")==-1)
				{
					nickName = "ie4";
				}
				if (nummer >= 4 && version.indexOf("msie 5.0")!=-1 && version.indexOf("msie 6")==-1)
				{
					nickName = "ie50";
				}
				if (nummer >= 4 && version.indexOf("msie 5.5")!=-1 && version.indexOf("msie 6")==-1)
				{
					nickName = "ie55";
				}
				if (nummer >= 4 && version.indexOf("msie 6")!=-1 && version.indexOf("msie 5")==-1)
				{
					nickName = "ie6";
				}
			}
			else
			{
				/* browser kenn ich nicht was machen? */
			}
		}
	}
	return nickName;
}