function openURL(URL)
     {
     window.open(URL)
     return false
     }
     function popup(URL,width,height)
     {
     window.open(URL,'_blank','width='+width+',height='+height+',resizable=0')
     return false
     }
//returns if email is valid 
function isValidEmail(Email){
if(window.RegExp) 
 {
  r_Email=RegExp("^[^@]+@[^.]+\..+$")
  if(r_Email.test(Email)){return true}
  else {return false}
 }
}
     
function UpdateFormFromCalendar(I_Day,I_Month,I_Year,I_Cal,X_lang)
{
switch(I_Cal)
{
 case(1):
 Xaddr = "index.php?center=book&lang="+X_lang+
                                       "&name="+document.getElementsByName("Name")[0].value+
                                       "&email="+document.getElementsByName("Email")[0].value+
                                       "&phone="+document.getElementsByName("Phone")[0].value+
                                       "&year="+I_Year+
                                       "&month="+I_Month+
                                       "&day="+I_Day+
                                       "&yearto="+document.getElementsByName("Year2")[0].value+
                                       "&monthto="+document.getElementsByName("Month2")[0].value+
                                       "&dayto="+document.getElementsByName("Day2")[0].value+
                                       "&adults="+document.getElementsByName("Adults")[0].value+
                                       "&children="+document.getElementsByName("Children")[0].value+
                                       "&note="+document.getElementsByName("Note")[0].value
                                       
                                      // alert(Xaddr)
                 window.open(Xaddr,"_self")
                 return false
 case(2):
  Xaddr = "index.php?center=book&lang="+X_lang+
                                       "&name="+document.getElementsByName("Name")[0].value+
                                       "&email="+document.getElementsByName("Email")[0].value+
                                       "&phone="+document.getElementsByName("Phone")[0].value+
                                       "&year="+document.getElementsByName("Year1")[0].value+
                                       "&month="+document.getElementsByName("Month1")[0].value+
                                       "&day="+document.getElementsByName("Day1")[0].value+
                                       "&yearto="+I_Year+
                                       "&monthto="+I_Month+
                                       "&dayto="+I_Day+
                                       "&adults="+document.getElementsByName("Adults")[0].value+
                                       "&children="+document.getElementsByName("Children")[0].value+
                                       "&note="+document.getElementsByName("Note")[0].value
                 window.open(Xaddr,"_self")
                 return false
 default:
 return true
 }
}


function isNumber(X)
{
if(window.RegExp) 
 {
r_Number=RegExp("^[0-9]+$")
if(r_Number.test(X)){return true}
else {return false}
}
}

//  input - stringe
//  phone number contains numbers and the first character might be "+"

function isPhoneNumber(XPhone)
{
if(window.RegExp) 
 {
  var r_Phone = new RegExp("^[+]?[0-9 ]+$")
//  window.alert(RegExp)
  if(r_Phone.test(XPhone)) return true;
  else return false;
}
else
{window.alert("RegExp not supported")}
}

function areDatesOK(Y1,M1,D1,Y2,M2,D2)
{
//alert("from"+D1+"/"+M1+"/"+Y1+"\nTo"+D2+"/"+M2+"/"+Y2)
DY = parseInt(Y2) - parseInt(Y1)
if(DY > 0) {return true}
DM = parseInt(M2) - parseInt(M1)
if(DY < 0) {return false} 
//now Y1 == Y2
if(DM > 0) {return true}
if(DM < 0) {return false}
//now M1 == M2
if(parseInt(D1)>=parseInt(D2)) {return false}
else {return true}
}

function ValidateForm(Form,language)
{
switch(language)
{
// ==================================P R E K L A D==========================================
 case('cs'):
  alert_name        = "Zadejte, prosím, Vaše jméno."
  alert_email       = "Zadejte, prosím, Váš email."
  alert_email_valid = Form.Email.value+" není platná emailová adresa"
  alert_phone       = "Zadejte, prosím, Vaše telefonní číslo."
  alert_phone_valid = Form.Phone.value+" není platné telefonní číslo"
  alert_arrival     = "Zadejte, prosím, datum příjezdu pomocí levého kalendáře"
  alert_departure   = "Zadejte, prosím, datum odjezdu pomocí pravého kalendáře"
  alert_dates       = "Datum příjezdu musí být menší než datum odjezdu."
  alert_adults      = "Musíte zadat počet osob"
  alert_children    = "Musíte zadat počet dětí"
  alert_persons     = "Musíte zadat alespoň jednu osobu"
  alert_capacity    = "Kapacita chaty je pouze 60 osob."
  confirm_children  = "Opravdu přijedou děti bez doprovodu?"
  break
 
 case('en'): 
  alert_name        = "Fill in your name, please."
  alert_email       = "Fill in your email, please."
  alert_email_valid = Form.Email.value+" is not a valid email address"
  alert_phone       = "Fill in your phone number, please."
  alert_phone_valid = Form.Phone.value+" is not a valid phone number"
  alert_arrival     = "Fill in the arrival date using the left calendar"
  alert_departure   = "Fill in the departure date using the right calendar"
  alert_dates       = "The arrival date must be lower than the departure date"
  alert_adults      = "Fill in the number of adult persons, please"
  alert_children    = "Fill in the number of children, please"
  alert_persons     = "At least one person must be accomodated"
  alert_capacity    = "The accomodation capacity is limited to 60 persons."
  confirm_children  = "Are you sure to book a room for children without adults?"
  break
 case('de'): break
// =============================K O N E C  P R E K L A D U==================================
}
with(Form) {
 if(Name.value==""||Name.value==null)
  {
  alert(alert_name);return false
  }
 // check Email
 else if(Email.value==""||Email.value==null)
  {
  alert(alert_email);return false
  }
 else if(!isValidEmail(Email.value))
  {
  alert(alert_email_valid);return false
  }
 // check Phone}
 else if(Phone.value==""||Phone.value==null)
  {
  alert(alert_phone);return false
  }
 else if(!isPhoneNumber(Phone.value))
  {
  alert(alert_phone_valid);return false
  }
 // check date1
 else if(!isNumber(Day1.value)||!isNumber(Month1.value)||!isNumber(Year1.value))
  {
  alert(alert_arrival);return false
  }
 else if(!isNumber(Day2.value)||!isNumber(Month2.value)||!isNumber(Year2.value))
  {
  alert(alert_departure);return false
  }
 else if(!areDatesOK(Year1.value,Month1.value,Day1.value,Year2.value,Month2.value,Day2.value))
  {
  alert(alert_dates);return false
  }
 else if(!isNumber(Adults.value))
  {
  alert(alert_adults);return false
  }
 else if(!isNumber(Children.value))
  {
  alert(alert_children);return false
  }
 else if(parseInt(Children.value)+parseInt(Adults.value)==0)
  {
  alert(alert_persons);return false
  }
else if(parseInt(Children.value)+parseInt(Adults.value)>60)
  {
  alert(alert_capacity);return false
  }
 else if(parseInt(Children.value)>0&&parseInt(Adults.value)==0)
  {
  if(confirm(confirm_children)==false){return false}
  } 
 else {return true}
 }
}

function checkMailtoForm(Form,language) {
switch(language)
{
// ==================================P R E K L A D==========================================
 case('cs'):
  alert_email_valid = Form.Email.value+" není platná emailová adresa"
  confirm_subject   = "Opravdu si přejete odeslat email bez předmětu?"
  alert_text        = "Nebyl zadán žádný text"
  break
 
 case('en'): 
  alert_email_valid = Form.Email.value+" is not a valid email address"
  confirm_subject   = "Are you sure to send the email without subject?"
  alert_text        = "Write us something..."
  break
 case('de'): break
}
// =============================K O N E C  P R E K L A D U==================================
with(Form) {
if(!isValidEmail(Email.value)) {alert(alert_email_valid);return false}
if(Subject.value==""||Subject.value==null)
  {if (!confirm(confirm_subject)) {return false}}
if(Text.value==""||Text.value==null) {alert(alert_text);return false}
return true
}
}

function checkForumForm(Form,language) {
switch(language){
// ==================================P R E K L A D==========================================
 case('cs'):
  alert_name        = "Zadejte prosím své jméno"
  alert_email_valid = Form.Email.value+" není platná emailová adresa.\nZadejte platnou emailovou adresu nebo nechte políčko nevyplněné"
  alert_text        = "Nelze přidat prázdný příspěvek"
  break
 
 case('en'): 
  alert_name        = "Fill in your name, please"
  alert_email_valid = Form.Email.value+" is not a valid email address.\nFill in a valid email address or leave the field blank"
  alert_text        = "You can not add an blank entry"
  break
 case('de'): break
 }
 // =============================K O N E C  P R E K L A D U==================================
with(Form)
{
if(Name.value=="" ||Name.value==null) {alert(alert_name);return false}
if(Email.value!=""&&Email.value!=null) {
 if(!isValidEmail(Email.value)) {alert(alert_email_valid);return false}
}
if(Text.value=="" ||Text.value==null) {alert(alert_text);return false}
}
}