var browser = navigator.userAgent.toLowerCase();
var ganzzahl = parseInt(navigator.appVersion);
var genauezahl = parseFloat(navigator.appVersion);
//ist es netscape
var netscap = ((browser.indexOf('mozilla')!=-1) && (browser.indexOf('spoofer')==-1) && (browser.indexOf('compatible') == -1) && (browser.indexOf('opera')==-1) && (browser.indexOf('webtv')==-1) && (browser.indexOf('hotjava')==-1));
//ist es netscape 6
var netscap6up = (netscap && (ganzzahl >= 5));
//oder firefox
var firefox = (browser.indexOf('firefox')!=-1)
//oder Opera
var opera = (browser.indexOf("opera") != -1);
var opera9 = (opera && (ganzzahl >=9));

//ist es internet explorer
var explorer = ((browser.indexOf("msie") != -1) && (browser.indexOf("opera") == -1));
var explorer3 = (explorer && (ganzzahl < 4));
var explorer4 = (explorer && (ganzzahl == 4) && (browser.indexOf("msie 5")==-1));
var explorer5 = (explorer && (ganzzahl == 4) && (browser.indexOf("msie 5.0")!=-1));
var explorer5_5up =(explorer && !explorer3 && !explorer4 && !explorer5);
var explorer6 = (explorer && (ganzzahl == 4) && (browser.indexOf("msie 6.0")));
var isOldBrowser = 1;
//variablen sind 1, wenn bedingung zutrifft, sonnst 0
if ((netscap && netscap6up) || opera9 || firefox ||explorer5_5up || explorer6) { isOldBrowser = 0; }