Spam protection for email addresses in forms

Hi,

does anybody has a solutions for this one.

I found something like this:
<script language=javascript>
<!--
var username = "username";
var hostname = "yourdomain.com";
var linktext = username + "@" + hostname;
document.write("<input type=hidden name=recipient value=" +username
+ "@" + hostname" + ">";
document.write(username + "@" + hostname);
//-->
</script>

I'm trying to replace the recipient field which contains the email address where I am getting the forms with this one. But my Formmail (Matts) always says no valid recipient specified.

Does anybody has a working solution?

thanks
Frank