function calc_to_date() {
  var form = document.forms['auto_search'];
  var from_date = form.elements['from_date'].value;
  var days_cnt = parseInt(form.elements['days_cnt'].value);

  var rental_hour = form.elements['rental_hour'].value;
  var return_hour = parseInt(form.elements['return_hour'].value);

  if (!days_cnt) {
    days_cnt = 1;
    form.elements['days_cnt'].value = 1;
  }

  if (from_date.length >= 6) {
    var from_date_array = from_date.split(".");
    if (from_date_array.length < 3) return;
    sday = from_date_array[0];
    if (sday.length == 1)
      sday = "0" + sday;
    smonth = from_date_array[1];
    if (smonth.length == 1)
      smonth = "0" + smonth;
    syear = from_date_array[2];

    var tmp_date = new Date(syear, smonth-1, sday);
    tmp_date.setDate(tmp_date.getDate()+days_cnt);

    dd = tmp_date.getDate();
    mm = tmp_date.getMonth()+1;
    yyyy = tmp_date.getYear();
    if (yyyy < 1000) yyyy += 1900; // Y2K fix   
    mymanth = "" + mm;
    myday = "" + dd;
    if (myday.length == 1)
      myday = "0" + myday;
    if (mymanth.length == 1) {
      mymanth = "0" + mymanth;
    }
    form.elements['to_date'].value = myday + '.' + mymanth + '.' + yyyy;
  }
}

function calc_nights() {
  var form = document.forms['auto_search'];
  var from_date = form.elements['from_date'].value;
  var to_date = form.elements['to_date'].value;
  var rental_hour = form.elements['rental_hour'].value;
  var return_hour = form.elements['return_hour'].value;


  if (from_date.length >= 6 && to_date.length >= 6 ) {
    var from_date_array = from_date.split(".");
    if (from_date_array.length < 3) return;
    sday = from_date_array[0];
    if (sday.length == 1)
      sday = "0" + sday;
    smonth = from_date_array[1];
    if (smonth.length == 1)
      smonth = "0" + smonth;
    syear = from_date_array[2];

    var start_date = new Date(syear, smonth-1, sday);

    var to_date_array = to_date.split(".");
    if (to_date_array.length < 3) return;
    sday = to_date_array[0];
    if (sday.length == 1)
      sday = "0" + sday;
    smonth = to_date_array[1];
    if (smonth.length == 1)
      smonth = "0" + smonth;
    syear = to_date_array[2];

    var end_date = new Date(syear, smonth-1, sday);

    if (start_date < end_date) {
       
     var form_days_cnt = Math.round((end_date.getTime()-start_date.getTime())/(24 * 60 * 60 * 1000));
     if (parseInt(return_hour) > parseInt(rental_hour)) {
       form_days_cnt = parseInt(parseInt(form_days_cnt)+1);
     }
     form.elements['days_cnt'].value = form_days_cnt; 

   } else {
      end_date.setDate(end_date.getDate()+1);
      form.elements['days_cnt'].value = 1;
    }
  }
}