HTTP_REFERER not set in html email - any ideas?

I'm creating a short html email to send to our existing customers which
consists of half a dozen questions on an html form (within the html email)
from which they use form radio buttons to pick their answer. They then click
on a submit button which links to a php script in our webspace. This all
works fine.

If this were simply a form on a webpage (as opposed to within an email) I'd
include something to check the HTTP_REFERER was what I was expecting to try
and avoid it being abused. However, because this is an html form within an
email, HTTP_REFERER is not set. Is there anything else I can test for to try
and make sure that use of the form only comes from the email questionnaires
we've sent out.

(I appreciate I could just email people a link to a webpage and run the
survey from the webpage but we're trying to make this as convenient as
possible for people to try and get as high a response rate as we can).

Many thanks, David

put an hidden field with the email address of the person to who u sent the
email if he already answear the data are not registered


"David" <mail@home.net> ha scritto nel messaggio
news:419b6a0b$0$33626$ed2619ec@ptn-nntp-reader02.plus.net...
> I'm creating a short html email to send to our existing customers which
> consists of half a dozen questions on an html form (within the html email)
> from which they use form radio buttons to pick their answer. They then
click
> on a submit button which links to a php script in our webspace. This all
> works fine.
>
> If this were simply a form on a webpage (as opposed to within an email)
I'd
> include something to check the HTTP_REFERER was what I was expecting to
try
> and avoid it being abused. However, because this is an html form within an
> email, HTTP_REFERER is not set. Is there anything else I can test for to
try
> and make sure that use of the form only comes from the email
questionnaires
> we've sent out.
>
> (I appreciate I could just email people a link to a webpage and run the
> survey from the webpage but we're trying to make this as convenient as
> possible for people to try and get as high a response rate as we can).
>
> Many thanks, David
>
>