function Check_Browser(URL,altURL) 
{ //fuer die Indexseite
  	var newURL = '';
  	var appN=navigator.appName;
  	var appV=navigator.appVersion;
  	var intPos=appV.indexOf('MSIE');
  	if (intPos>0) 
  	{
  		var bln1=appV.charAt(intPos+5)>'5';
		var bln2=appV.charAt(intPos+5)=='5';
		var bln3=appV.charAt(intPos+7)=='5';
		if ( bln1 || (bln2 && bln3))
   		{
   			newURL=URL;
   		}
   		else 
   		{	
   			if (appV.charAt(intPos+5)>='4')
   				newURL=altURL;
   		}
  	}
  	else 
  	{
  		if (appN=='Netscape')
  		{
  			if (parseFloat(appV)>=4)
  			{
  				newURL=altURL;
  			}
  		}
  	}
  	if (newURL) 
  	{
   		window.location = newURL;
  	}
}