function empty(x) { if (x.length > 0) return false; else return true; }
var $prev_country = "";
function check_country() {
  $pc = document.order.country.value ;
  if($pc != $prev_country && ($pc == "**" || $prev_country == "**")) {
    toggle_display('paypal-button');
    toggle_display('nopaypal-msg');
  }
  $prev_country = $pc;
  set_shipby($pc);
  return;
}
var $express = new Array();
var $express_desc = new Array();
var $priority = new Array();
var $priority_desc = new Array();
$express["AU"]=1;
$express_desc["AU"]="Express Mail";
$express["CA"]=1;
$express_desc["CA"]="Express Mail";
$express["US"]=1;
$express_desc["US"]="Express Mail";
function set_shipby($ccode){ // set shipby options available for chosen country
  i = 0;
  document.order.shipby.options[i++] = 
         new Option("Air Mail", "Air");
  if($express[$ccode]) document.order.shipby.options[i++] = 
         new Option($express_desc[$ccode], "Express");
  if($priority[$ccode]) document.order.shipby.options[i++] = 
         new Option($priority_desc[$ccode], "Priority");
  // delete any remaining  
  while(i<document.order.shipby.options.length) 
    document.order.shipby.options[i++] = null;
  return;
}

function check_shipby(){
  var shipby = document.order.shipby.value;
  var quantity = document.order.quantity.value;

  if(shipby != "Air" && quantity != "1") {
       alert("Only AirMail available for Multiple DVDs\n");
     document.order.shipby.value = "Air";
  }
}

function check_quantity(){
  var shipby = document.order.shipby.value;
  var quantity = document.order.quantity.value;

  if(shipby != "Air" && quantity != "1") {
       alert("Choose Air Mail shipping for Multiple DVDs\n");
     document.order.quantity.value = "1";
  }
}

function validate() {
 var missing = ""; 
 var country =document.order.country.value;
 if(empty(document.order.firstname.value)) missing += "First Name " ;
 if(empty(document.order.lastname.value) && document.order.item_number.value=="NanoP") missing += "Last Name ";
 if(empty(document.order.address1.value))  missing += "Address ";
 if(empty(document.order.city.value))  missing += "City ";
 if(empty(document.order.country.value))  missing += "Country ";
 if((country == "CA" || country == "US") && empty(document.order.zip.value)) missing += "Zip "; 
 if((country == "CA" || country == "US") && empty(document.order.state.value)) missing += "State "; 
 if(empty(document.order.email.value)) missing += "Email ";
 if(missing) {
   alert("The following required fields are empty: "+missing+". Please fill in these and try again.");
   return false;
 }
 if (document.order.email.value != document.order.email1.value){
   alert('The email addresses do not match. Please try again.');
   return false;
 }
 return true;
}

function order_bycheque() {
    if(!validate()) return;
    document.order.action = "order_bycheque.php";
    document.order.submit();
}