function prevyear() {
  var f = document.getElementById('senddate');
  var y = document.getElementById('year');
  var fdate = document.getElementById('fdate');
  var ldate = document.getElementById('ldate');
  var m = document.getElementById('month');

    if (m.value.length==1) {
        mm = '0' + m.value;
    }
    else {
        mm = m.value;
    }
    y.value=y.value-1;
    fdate.value = '01' + '.' + mm + '.' + y.value;
    ldate.value = '31' + '.' + mm + '.' + y.value;
    f.submit();
}

function nextyear() {
  var f = document.getElementById('senddate');
  var y = document.getElementById('year');
  var fdate = document.getElementById('fdate');
  var ldate = document.getElementById('ldate');
  var m = document.getElementById('month');

    pp = parseInt(y.value);
    y.value = pp+1;
    if (m.value.length==1) {
        mm = '0' + m.value;
    }
    else {
        mm = m.value;
    }
    fdate.value = '01' + '.' + mm + '.' + y.value;
    ldate.value = '31' + '.' + mm + '.' + y.value;
    f.submit();
}

function prevmonth() {
  var f = document.getElementById('senddate');
  var m = document.getElementById('month');
  var mm = parseInt(m.value);
  var y = document.getElementById('year');
  var yy = parseInt(y.value);
  var fdate = document.getElementById('fdate');
  var ldate = document.getElementById('ldate');

   if (mm==1) {
     m.value = 12;
     y.value = yy-1;
   }
   else {
     m.value = mm-1;
   }
   if (m.value.length==1) {
        mx = '0' + m.value;
   }
   else {
        mx = m.value;
   }
   fdate.value = '01' + '.' + mx + '.' + y.value;
   ldate.value = '31' + '.' + mx + '.' + y.value;
   f.submit();
}

function nextmonth() {
  var f = document.getElementById('senddate');
  var m = document.getElementById('month');
  var mm = parseInt(m.value);
  var y = document.getElementById('year');
  var yy = parseInt(y.value);
  var fdate = document.getElementById('fdate');
  var ldate = document.getElementById('ldate');

   if (mm==12) {
     m.value = 1;
     y.value = yy+1;
   }
   else {
     m.value = mm+1;
   }
   if (m.value.length==1) {
        mx = '0' + m.value;
   }
   else {
        mx = m.value;
   }
   fdate.value = '01' + '.' + mx + '.' + y.value;
   ldate.value = '31' + '.' + mx + '.' + y.value;
   f.submit();
}

function Showyear() {
  var f = document.getElementById('senddate');
  var fdate = document.getElementById('fdate');
  var ldate = document.getElementById('ldate');
  var y = document.getElementById('year');
  var oy = document.getElementById('oy');

   pp = parseInt(y.value);
   yy = pp+1;
   fdate.value = '01' + '.' + '01' + '.' + y.value;
   ldate.value = '01' + '.' + '01' + '.' + yy;
   oy.value = 'true';
   f.submit();
}

function Showmonth() {
  var f = document.getElementById('senddate');
  var fdate = document.getElementById('fdate');
  var ldate = document.getElementById('ldate');
  var m = document.getElementById('month');
  var y = document.getElementById('year');

   if (m.value.length==1) {
        mx = '0' + m.value;
   }
   else {
        mx = m.value;
   }
   fdate.value = '01' + '.' + mx + '.' + y.value;
   ldate.value = '31' + '.' + mx + '.' + y.value;
   f.submit();
}