function isEmpty(s) 
{   
// Check whether string s is empty.
    return ((s == null) || (s.length == 0))
}

function validateEmailv2(email)
{
// a very simple email validation checking. 
// you can add more complex email checking if it helps 
    if((email == null) || (email.length == 0))
	{
	  return false;
	}
    var splitted = email.match("^(.+)@(.+)$");
    if(splitted == null) return false;
    if(splitted[1] != null )
    {
      var regexp_user=/^\"?[\w-_\.]*\"?$/;
      if(splitted[1].match(regexp_user) == null) return false;
    }
    if(splitted[2] != null)
    {
      var regexp_domain=/^[\w-\.]*\.[A-Za-z]{2,4}$/;
      if(splitted[2].match(regexp_domain) == null) 
      {
	    var regexp_ip =/^\[\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\]$/;
	    if(splitted[2].match(regexp_ip) == null) return false;
      }// if
      return true;
    }
    return false;
}

function update_sums()
{
    var thisform = document.congform;
    var tmp = Math.abs(thisform.totalAccommodation.value);
    thisform.swiftamount.value = tmp;
    thisform.grandTotal.value = tmp;
    thisform.chequeamount.value = tmp;
}


function calc_hotel()
{
//*****************************/
//   E - HOTEL ACCOMMODATION   /
//*****************************/
    var thisform = document.congform;
    var hotelfee, splitString;

    var arrivalDate   = parseInt(thisform.arrival.value);
    var departureDate = parseInt(thisform.departure.value);
    if (arrivalDate <  departureDate)
        thisform.nights.value = departureDate - arrivalDate;
    else
        thisform.nights.value = 0;
        
    for (i=0; i < thisform.hotel.length; i++)       
        if (thisform.hotel[i].checked == true) {
            splitString  = (thisform.hotel[i].value).split("€");
            hotelfee = parseInt(splitString[1]);
            break;
        }
        else
            hotelfee = 0;

    thisform.totalAccommodation.value = hotelfee * thisform.nights.value;
    update_sums();
} 
    
    // Function to validate the required fields for the form submition (English Form)
    function validate_form(){
        var thisform = document.congform;
            
            if (isEmpty(thisform.surname_required.value))
            {
                alert("Please write your Last Name.");
                thisform.surname_required.focus();
                return false;
            }
            else if((thisform.firstname_required.value == "")||(thisform.firstname_required.value == " "))
            {
                alert("Please write your First Name.");
                thisform.firstname_required.focus();
                return false;
            }
            else if((thisform.address_required.value == "")||(thisform.address_required.value == " "))
            {
                alert("Please write your Address.");
                thisform.address_required.focus();
                return false;
            }
            else if((thisform.city_required.value == "")||(thisform.city_required.value == " "))
            {
                alert("Please write your City.");
                thisform.city_required.focus();
                return false;
            }
            else if((thisform.country_required.value == "")||(thisform.country_required.value == " "))
            {
                alert("Please select your Country.");
                thisform.country_required.focus();
                return false;
            }
            else if((thisform.postalcode_required.value == "")||(thisform.postalcode_required.value == " "))
            {
                alert("Please write your Postal Code.");
                thisform.postalcode_required.focus();
                return false;
            }
            else if((thisform.phone_required.value == "")||(thisform.phone_required.value == " "))
            {
                alert("Please write your Phone.");
                thisform.phone_required.focus();
                return false;
            }
            else if(!validateEmailv2(thisform.email_required.value))
            {
                alert("Please enter a proper email address.");
                thisform.email_required.focus();
                return false;
            }
            else
                return true;
    }//function validate_form(){