function showCommercialFields(){
  var obj = document.getElementById('type');
  var commercialBlock = document.getElementById('commercial');
  var amountField = document.getElementById('amount');

  if(obj.selectedIndex==0){
    commercialBlock.style.display='none';
  }else{
    commercialBlock.style.display='block';
  }
  
  setPrice();

}

function setPrice(){
  var obj = document.getElementById('type');
  var amountField = document.getElementById('amount');  
  var support = document.getElementById('support');  
  var totalPrice;
  
  if(obj.selectedIndex == 0){
    totalPrice = 0;  
  }else if(obj.selectedIndex == 1){
    totalPrice = price1Year;
  }else{
    totalPrice = pricePermanent;
  }
  
  if(support.checked){
    totalPrice += priceSupport;
  }
  
  amountField.value = totalPrice+'';
}

function canSubmit(){
  //validate input here
  var retVal = true;
  var errors ='';
  var email = document.getElementById('email').value;
  var hostname = document.getElementById('hostname').value;
  var name = document.getElementById('OFName').value;
  
  if(name == ''){
    retVal = false;
    errors += "-You must provide your name.\n";  
  }
  
  if(!email.match(".@[-a-zA-Z0-9]+\(\\.[-a-zA-Z0-9]+\)+$")){
    retVal = false;
    errors += "-The email address doesn't seem to be valid.\n";
  }
  
  if(!hostname.match("^[a-zA-Z0-9-_][a-zA-Z0-9-_]+\(\\.[a-zA-Z0-9-_]+\)*$")){
    retVal = false;
    errors += "-The hostname doesn't seem to be valid.\n";
  }
  
  if(errors){
    alert("Your form could not be submitted because of the following errors:\n"+errors);
  }
  
  return retVal;
}