function roll_over(img_name, img_src) {
      document[img_name].src = img_src;
    }
     
    function zmen(select, changeSel) {
      var list = document.getElementById(changeSel);
      while (list.childNodes[0]) {
        list.removeChild(list.childNodes[0])
      }
      var selMonthYear = select.value.replace(/-/,"");
    
      var delka = eval("pole" + selMonthYear + ".length");
    
      for (i = 0; i < delka; i++) {
        var value = eval("pole"+selMonthYear+"["+i+"]");
        var name = eval("pole"+selMonthYear+"days["+i+"]");
        
        var x = document.createElement('option');
        var y = document.createTextNode(name);
        
        x.setAttribute('value',value);
        if (i == 0) {
          x.setAttribute('selected','selected');
        }
        x.appendChild(y);
        list.appendChild(x);
      }
    }
    
    function thick(checkbox, status) {
      var checkb = document.getElementById(checkbox);
      checkb.checked = status;
    }
    
    function myFormatDate(inputdate) {
      var curr_date = inputdate.getDate();
      var curr_date_str = "";
      var curr_month = parseInt(inputdate.getMonth()) + 1;
      var curr_month_str = "";
      var curr_year = inputdate.getFullYear();
      
      if (parseInt(curr_date) < 10) {
        curr_date_str = "0" + curr_date;
      } else {
        curr_date_str = "" + curr_date;
      }
      
      if (parseInt(curr_month) < 10) {
        curr_month_str = "0" + curr_month;
      } else {
        curr_month_str = "" + curr_month;
      }
      
      var retValue = "" + curr_year + "-" + curr_month_str + "-" + curr_date_str;
      
      return retValue;
    }
    
    function showEndDate() {
      var startday = document.getElementById('daySelect');
      var startmy = document.getElementById('monthYearSelect');
      var nightscnt = document.getElementById('nightscnt');
      
      var startdayvalue = startday.options[startday.selectedIndex].value;
      var startmyvalue = startmy.options[startmy.selectedIndex].value;
      var nightscntvalue = nightscnt.options[nightscnt.selectedIndex].value;
      
      var startYear = startmyvalue.substring(0,4); /* rok */
      var startMonth = startmyvalue.substring(5); /* mesic */
      var startDay = startdayvalue; /* den */
      
      if (startMonth.substring(0,1) == 0) {
        startMonth = startMonth.substring(1,2);
      }
      startMonth = startMonth - 1; /* v JavaScriptu jsou mesice cislovany 0 - 11 */
      if (startDay.substring(0,1) == 0) {
        startDay = startDay.substring(1,2);
      }
      
      var endDate=new Date();
      endDate.setFullYear(startYear,startMonth,startDay);
      var endDateValue = parseInt(endDate.getDate()) + parseInt(nightscntvalue);
      endDate.setDate(endDateValue);
      
      var endDayInput = document.getElementById('endDaySelect');
      var endmyInput = document.getElementById('endMonthYearSelect');
      
      endDayInput.value = myFormatDate(endDate).substring(8,10);
      endmyInput.value = myFormatDate(endDate).substring(0,7);
      
      var enddatumtext = document.getElementById('enddatumtext');
      var selMonthYear = myFormatDate(endDate).substring(0,7).replace(/-/,"");
            
      var itxtfull = myFormatDate(endDate).substring(8,10);
      var itxt = myFormatDate(endDate).substring(8,10);
      if (itxt.substring(0,1) == 0) {
        itxt = itxt.substring(1,2);
      }
      var jtxt = myFormatDate(endDate).substring(5,7);
      if (jtxt.substring(0,1) == 0) {
        jtxt = jtxt.substring(1,2);
      }
      var index = 0;
      var delka = eval("pole" + selMonthYear + ".length");
    
      for (i = 0; i < delka; i++) {
        var value = eval("pole"+selMonthYear+"["+i+"]");
        if (value == itxtfull) {
          index = i;
          break;
        }
      }
      
      var name = eval("pole"+selMonthYear+"days["+ index +"]");
      var mesic = eval("monthNamesArray["+ eval(parseInt(jtxt)-1) +"]");
      
      
            
      enddatumtext.value = name + " " + mesic + " " + myFormatDate(endDate).substring(0,4);;
    }
    
    function resetForm() {
      var form = document.getElementById('form1');
      form.reset();
    }