At a minimum, MailSerf needs to have the To: field of the mail header specified. This is required because the generated e-mail message needs to have a destination. Note that if no e-mail address is specified, MailSerf will not send the mail but will respond with an error message.
The following HTML code produces a form that will send the value of the Comment field to the specified Internet mail address....
<form action="/cgi-bin/mailserf" method="POST">
Comment: <input type="text" name="Comment" size="50"><br>
E-mail address: <input type="text" name="hdr:to"><p>
<input type="submit" value="Send message">
</form>