var is_Win = false;    // wahr wenn Windows Plattform
var is_Mac = false;    // wahr wenn Macintosh Plattform

var is_Nav = false;    // wahr wenn Netscape Navigator Browser (noch keine Version)
var is_Msi = false;    // wahr wenn Internet Explorer Browser (noch keine Version)
var is_Moz = false;    // wahr wenn Mozilla Browser (noch keine Version)
var is_Ope = false;    // wahr wenn Opera Browser (noch keine Version)

var browser = '';
var os = '';

var chk = true;
var uAgent = navigator.userAgent.toLowerCase();



/*
* Welches System hat der User (Win.Mac)
*/

if ((uAgent.indexOf("win")!= -1) || (uAgent.indexOf("16bit")!= -1)) {
  is_Win = true;
  os = 'Windows';
}

if (uAgent.indexOf("mac")!= -1) {
  is_Mac = true;
  os = 'Macintosh';
}



/*
* Welcher Browser (ohne Version)
*/
if ((uAgent.indexOf('mozilla') != -1) && (uAgent.indexOf('spoofer')== -1) && (uAgent.indexOf('compatible') == -1) && (uAgent.indexOf('opera') == -1)) {
  if ((uAgent.indexOf('rv:1.') != -1) && (uAgent.indexOf("netscape") == -1)) {
    is_Moz = true;
    browser = 'Firefox'
  } else {
    is_Nav = true;
    browser = 'Netscape';
  }
}
if ((uAgent.indexOf("msie") != -1) && (uAgent.indexOf("opera") == -1)) {
  is_Msi = true;
  browser = 'Internet Explorer';
}
if (uAgent.indexOf("opera") != -1) {
  is_Ope = true;
  browser = 'Opera';
}