how to send email using php or javascript or Jquery?

// Code from link attached

$to      = 'nobody@example.com';
$subject = 'the subject';
$message = 'hello';
$headers = 'From: webmaster@example.com';

// send email
mail($to, $subject, $message, $headers);
?>

$.ajax({
   // URL where your PHP code is
   url: 'send-email.php'
   // if sent
   success: function(data) {
     alert('Email sent');
   }
});