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 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(isEmpty(thisform.firstname_required.value)) {
        alert("Please write your First Name.");
        thisform.firstname_required.focus();
        return false;
    } else if(isEmpty(thisform.address_required.value)) {
        alert("Please write your Address.");
        thisform.address_required.focus();
        return false;
    } else if(isEmpty(thisform.city_required.value)) {
        alert("Please write your City.");
        thisform.city_required.focus();
        return false;
    } else if(isEmpty(thisform.country_required.value)) {
        alert("Please select your Country.");
        thisform.country_required.focus();
        return false;
    } else if(isEmpty(thisform.postalcode_required.value)) {
        alert("Please write your Postal Code.");
        thisform.postalcode_required.focus();
        return false;
    } else if(isEmpty(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 if(!thisform.paymentform[0].checked && !thisform.paymentform[1].checked && !thisform.paymentform[2].checked) {
        alert("Please select the payment form");
        return false;
    } else if(thisform.paymentform[0].checked) {
        if (isEmpty(thisform.bankdraftnum.value)) {
            alert("Please write the cheque number" + '\n' + "(Certified Bank Cheque fields)");
            thisform.bankdraftnum.focus();
            return false;
        } 
        if (isEmpty(thisform.bank.value)) {
            alert("Please write bank name" + '\n' + "(Certified Bank Cheque fields)");
            thisform.bank.focus();
            return false;
        } 
    } else if(thisform.paymentform[1].checked) {
        if (isEmpty(thisform.bankname.value)) {
            alert("Please write the bank name" + '\n' + "(Swift Bank Transfer fields)");
            thisform.bankname.focus();
            return false;
        }
        if (isEmpty(thisform.bankcity.value)) {
            alert("Please write the bank city" + '\n' + "(Swift Bank Transfer fields)");
            thisform.bankcity.focus();
            return false;
        } 
    } else return true;
}