function validate(form){
 var errors = [];
 
 if ( !checkSelect(form.prod_price) ) {
  errors[errors.length] = "You must choose a size.";
 }

 if ( !checkSelect(form.prod_custom1) ) {
  errors[errors.length] = "You must choose an option.";
 }
 
 if (errors.length > 0) {
  reportErrors(errors);
  return false;
 }
 
 return true;
}

function checkSelect(select){
 return (select.selectedIndex > 0);
}

function reportErrors(errors){
 var msg = "";
 var numError;
 for (var i = 0; i<errors.length; i++) {
  numError = i + 1;
  msg += "\n" + numError + ". " + errors[i];
 }
 alert(msg);
}
  
function validate2(form){
 var errors = [];
 
 if ( !checkSelect(form.prod_price) ) {
  errors[errors.length] = "You must choose a size.";
 }
 
 if (errors.length > 0) {
  reportErrors(errors);
  return false;
 }
 
 return true;
}

function checkSelect(select){
 return (select.selectedIndex > 0);
}

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