As others have said, for your specific case, I would bypass the whole remote thing and have the original script send the email.

If that's not possible, or for other situations, I sometimes use an image link that points to a second/remote script, which does whatever it needs to do and just returns a single pixel image to the browser.*

* This technique is often referred to as a 'web bug', and though it has a bad rap for inappropriate and malicious use by banner advertisers and spammers, the technique itself is often perfect for legitimate purposes as well.

cheers!