function updateRange(from) {
  
  var submit_button = document.getElementById('submit_button');
  submit_button.disabled = true;
  
  var begin_day = document.getElementById('begin_day');
  var begin_day_selected = begin_day.options[ begin_day.selectedIndex ];
  var begin_day_value = begin_day_selected.value;
  
  var begin_month = document.getElementById('begin_month');
  var begin_month_selected = begin_month.options[ begin_month.selectedIndex ];
  var begin_month_value = begin_month_selected.value;
  
  var begin_year = document.getElementById('begin_year');
  var begin_year_selected = begin_year.options[ begin_year.selectedIndex ];
  var begin_year_value = begin_year_selected.value;
  
  var end_day = document.getElementById('end_day');
  var end_day_selected = end_day.options[ end_day.selectedIndex ];
  var end_day_value = end_day_selected.value;
  
  var end_month = document.getElementById('end_month');
  var end_month_selected = end_month.options[ end_month.selectedIndex ];
  var end_month_value = end_month_selected.value;
  
  var end_year = document.getElementById('end_year');
  var end_year_selected = end_year.options[ end_year.selectedIndex ];
  var end_year_value = end_year_selected.value;
  
  /* set hidden values */
  
  var begin_date_hidden = document.getElementById('begindate_hidden');
  begin_date_hidden.value = begin_year_value+'/'+begin_day_value+'/'+begin_month_value;
  
  var end_date_hidden = document.getElementById('enddate_hidden');
  end_date_hidden.value = end_year_value+'/'+end_day_value+'/'+end_month_value;
  
  submit_button.disabled = false;
  
}

function updateRangeFromPicker() {
  
  var submit_button = document.getElementById('submit_button');
  submit_button.disabled = true;
  
  var begin_date_hidden = document.getElementById('begindate_hidden');
  var begin_date_array  = begin_date_hidden.value.split("/");
  
  selectValue('begin_year', begin_date_array[0]);
  selectValue('begin_day', begin_date_array[1]);
  selectValue('begin_month', begin_date_array[2]);
  
  var end_date_hidden = document.getElementById('enddate_hidden');
  var end_date_array  = end_date_hidden.value.split("/");
  
  selectValue('end_year', end_date_array[0]);
  selectValue('end_day', end_date_array[1]);
  selectValue('end_month', end_date_array[2]);
  
  submit_button.disabled = false;
  
}

function selectValue(selectName, value) {
  
  SelectObject = document.getElementById(selectName);
  
  for(index = 0; index < SelectObject.length; index++) {
    
    if(SelectObject[index].value == value) {
      SelectObject.selectedIndex = index;
    }
    
  }
  
}

function submitButton() {
  
  var submit_button = document.getElementById('submit_button');
  submit_button.disabled = true;
  
  document.reservationform.submit();
  
}

function dateIsValid(thisDate) {
  
  today = new Date();
  
  if(thisDate <= today) {
    return true;
  }
  else if(thisDate.getFullYear() > (today.getFullYear()+1) ) {
    return true;
  }
  else {
    return false;
  }
  
}