function check() {
var valideur = 0;
valideur = valideur + eval(document.feedback.jahr1.value) + eval(document.feedback.monat1.value) + eval(document.feedback.tag1.value) + eval(document.feedback.jahr2.value) + eval(document.feedback.monat2.value) + eval(document.feedback.tag2.value);
if (valideur < 4012) 
{
document.feedback.tagdiff.value="";
return false;
}
else tagdiff_berechnen();
}
function idiv (dividend, divisor) {
return Math.floor (dividend / divisor);
}
function leapyear (year) {
return ((year & 3) == 0) && (((year % 100) != 0) || ((year % 400) == 0));
}
function dayspermonth (year, month) {
dpm = new Array (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
month--;
var result = dpm [month];
if (month == 1) if (leapyear (year)) result++;
return result;
}
function date_ok (year, month, day) {
if (year < 1582) return 0;
if (year == 1582) if (month < 10) return 0;
if (year == 1582) if (month == 10) if (day < 15) return 0;
if ((month < 1) || (month > 12)) return 0;
if ((day < 1) || (day > dayspermonth (year, month))) return 0;
return 1;
}
function juldate (year, month, day) {
var kyear;
var kmonth;
var result = -1;
if (year == 0) return result;
if (month < 3) {
kmonth = month + 12;
kyear = year - 1;
}
else {
kmonth = month;
kyear = year;
}
kmonth++;
result = kyear * 365 + idiv (kyear, 4) + idiv ((kmonth * 306), 10) + day + 1720995;
if (result > 2299170) {
result = result - idiv (kyear, 100) + idiv (kyear, 400) + 2;
}
else if (result > 2299160) {
result = result - idiv (kyear, 100) + idiv (kyear, 400) + 2 + 10;
}
return result;
}
function wotag (wt) {
wotage = new Array ("Montag", "Dienstag", "Mittwoch", "Donnerstag",
"Freitag", "Samstag", "Sonntag", "Datum ungueltig!");
return wotage [wt];
}
function monat (mo) {
monate = new Array ("Januar", "Februar", "Maerz", "April",
"Mai", "Juni", "Juli", "August",
"September", "Oktober", "November", "Dezember",
"Datum ungueltig!");
return monate [--mo];
}
function wota_berechnen () {
var year = eval (document.ewig.jahr.value);
var month = eval (document.ewig.monat.value);
var day = eval (document.ewig.tag.value);
if (year < 100) {
year += 1900;
document.ewig.jahr.value = year;
}
var wota = juldate (year, month, day) % 7;
if (date_ok (year, month, day) == 0) wota = 7;
document.ewig.wochentag.value = wotag (wota);
}
function monat_im_jahr (year, n) {
var a = 0;
if (leapyear (year)) a++;
if (n > 59 + a) n += 2 - a;
n += 91;
return idiv ((20 * n), 611) - 2;
}
function tag_im_monat (year, n) {
var a = 0;
if (leapyear (year)) a++;
if (n > 59 + a) n += 2 - a;
n += 91;
var m = idiv ((20 * n), 611);
return n - idiv (611 * m, 20);
}
function ostersonntag (year) {
var gz = (year % 19) + 1;
var jhd = idiv (year, 100) + 1;
var ksj = idiv ((3 * jhd), 4) - 12;
var korr = idiv ((8 * jhd + 5), 25) - 5;
var so = idiv ((5 * year), 4) - ksj - 10;
var epakte = (11 * gz + 20 + korr - ksj) % 30;
if (((epakte == 25) && (gz > 11)) || (epakte == 24)) epakte++;
var n = 44 - epakte;
if (n < 21) n += 30;
n = n + 7 - (so + n) % 7;
if (leapyear (year)) n++;
return n + 59;
}
function wota_datum (year, month, day) {
var wota;
if (date_ok (year, month, day) == 0) {
return wotag (7)
}
else {
wota = juldate (year, month, day) % 7;
return wotag (wota) + ", " + day + ". " + monat (month) + " " + year;
}
}
function feiertage_berechnen () {
var year = eval (document.feiertage.fjahr.value);
if (year < 100) {
year += 1900;
document.feiertage.fjahr.value = year;
}
var dnum0 = ostersonntag (year);
var dnum = dnum0;
var month = monat_im_jahr (year, dnum);
var day = tag_im_monat (year, dnum);
document.feiertage.osterdatum.value = wota_datum(year, month, day);
dnum = dnum0 + 39;
month = monat_im_jahr (year, dnum);
day = tag_im_monat (year, dnum);
document.feiertage.chrhidatum.value = wota_datum(year, month, day);
dnum = dnum0 + 49;
month = monat_im_jahr (year, dnum);
day = tag_im_monat (year, dnum);
document.feiertage.pfidatum.value = wota_datum(year, month, day);
dnum = dnum0 + 60;
month = monat_im_jahr (year, dnum);
day = tag_im_monat (year, dnum);
document.feiertage.fronldatum.value = wota_datum(year, month, day);
dnum = dnum0 - 46;
month = monat_im_jahr (year, dnum);
day = tag_im_monat (year, dnum);
document.feiertage.aschmdatum.value = wota_datum(year, month, day);
month = 8;
day = 15;
document.feiertage.mariahdatum.value = wota_datum(year, month, day);
month = 12;
day = 24;
document.feiertage.wndatum.value = wota_datum(year, month, day);
}


function tagdiff_berechnen () {
var year1 = eval (document.feedback.jahr1.value);
var month1 = eval (document.feedback.monat1.value);
var day1 = eval (document.feedback.tag1.value);
var year2 = eval (document.feedback.jahr2.value);
var month2 = eval (document.feedback.monat2.value);
var day2 = eval (document.feedback.tag2.value);
if (year1 < 100) {
year1 += 1900;
document.feedback.jahr1.value = year1;
}
if (year2 < 100) {
year1 += 1900;
document.feedback.jahr2.value = year2;
}
var po1 = juldate (year1, month1, day1);
var po2 = juldate (year2, month2, day2); 

if ((date_ok (year1, month1, day1) == 0) || (date_ok (year2, month2, day2) == 0)) {
document.feedback.tagdiff.value = wotag (7)
}
else {
document.feedback.tagdiff.value = juldate (year2, month2, day2) - juldate (year1, month1, day1);
}
if (document.feedback.tagdiff.value < 1)
{
document.feedback.tagdiff.value="";
return false;
}
var zz=document.feedback.tagdiff.value;
if (isNaN(zz))
return true;
else
{
if (zz == 1)
zz = zz+" Tag";
else
zz = zz+" Tage";
document.feedback.tagdiff.value = zz;
//document.feedback.tagdiff.value = (zz==1) ?  zz+"Tag" :  zz+"Tage";
}
}
function ticker()
{
document.images.hinher.src="images/aktuell1.gif";
setTimeout("ticker1()",350);
}
function ticker1()
{
document.images.hinher.src="images/aktuell.gif";
setTimeout("ticker()",350);
}