function validate(form){
 var errors = [];

 if ( !checkRadioArray(form.pay) ) {
  errors[errors.length] = "Your Payment!.";
 }
 
 if (form.name1.value == "" && form.surname1.value == ""){
   errors[errors.length] = "Your Surname!.";
 }
 
 if (form.country.value == ""){
   errors[errors.length] = "Your Nationality!.";
 }
 
 if (form.email.value == ""){
   errors[errors.length] = "Your Email!.";
 }

 if (errors.length > 0) {
  reportErrors(errors);
  return false;
 }

 return true;
}

function checkRadioArray(radioButtons){
 for (var i=0; i < radioButtons.length; i++) {
  if (radioButtons[i].checked) {
   return true;
  }
 }
 return false;
}

function reportErrors(errors){
 var msg = "Please fill-in:\n";
 var numError;
 for (var i = 0; i<errors.length; i++) {
  numError = i + 1;
  msg += "\n" + numError + ". " + errors[i];
 }
 alert(msg);
}