You have to add attribute , ” required ” to all the input fields so that an error message will be displayed when one is empty!!
To check if the answer is correct, you can use php!
$name=$_GET["name"];
$email=$_GET["email"];
$ans=$_GET["ans"];
if($ans=='correct'){
// you can use mail command here
header("location:correct.php");
}else{
header("location:incorrect.php");
}
solved php radio buttons submit form issue