correct way to ID hidden fields in html for form submission

[Rae05]

I'm an html coder and I want to identify from what website a user has submitted a contact form. The contact form is an <!--#include>file (.shtml) and this contact form include file is being used on two different websites. Since it's only one include. I thought about adding two hidden fields to the include contact form with IDs of the two different sites:

<input type="hidden" data-id="new_student_signup" name="new_student_signup" value="" />
<input type="hidden" data-id="existing_student_signup" name="existing_student_signup" value="" />

But I'm not sure this will work since it's only one file. Here's why:

1. If its just one include file, how is the form going to know what site it came from?
   
2. Does it require a programming scripting language to get information from a hidden field in html, and if so, will my adding the two hidden input fields (with the data-id="" attribute) be sufficient for the html part of the <!--#include> file?
   
3. Should I just create a new include file for the other website and add the hiddenfield to that file?

Example:
for the hidden field "new_student_signup"

<!--#include virtual="new_students/existing_student_signup.shtml>

for the hidden field "existing_student_signup"

<!--#include virtual="existing_students/new_student_signup.shtml>

Thanks

[Fou-Lu]

In a web world, there are not very many options. HTTP is stateless, so your options are literally get, post, put, cookie and a few headers.
Most web processing languages do have the ability to use sessions, and can fetch information like the referrer and file specific data.

If you are talking about a remote site, then you cannot do anything to force this without individual specific files. A virtual include isn't really sufficient to perform this task as its not capable of detecting the "client" information (the remote) and populating off of it. Should this be a processable language such as PHP, JSP or Perl then you should be able to request the page from a remote site and provide it with the extra information required though a querystring. This can be used within the form to pass a hidden field. So instead the remote asks for somescript.php?siteid=1234, and you can use this information to generate some token data for use in the html form.

Also, is there a reason this is posted in Java or can this be moved to general web building?