Passing a hidden variable to another html page

OK, you probably can't do this, but if you can I'm sure one of you can help me. I'll keep it simple. I have 3 html pages, one for each product. There's a button on each page that takes you to another html page with a form on it, which sends the information to a php sendmail script. I need to be able to pass a hidden variable from the product pages, into a hidden field in the form, which will then place that info into the email that the sendmail script sends me. The hidden variable will tell me which of the 3 products the customer is interested in, depending on which product page they're going to the form page from. Can I do that or does at least one of the html pages have to be a php page? Now, if someone can help me I have NO knowledge of php at all, so I'll need the whole solution, not just "add this line, echo=('variable/n'). That should do it." I won't know where to put it. Sorry to be such a pain, but I'd appreciate any help anybody can give me.
M7

How do I pass a hidden variable on one html page to another html page with a form on it? The form has spaces for name, company, phone number, etc. which is sent to a php sendmail script on the server which emails the information to me. I need to have that hidden variable included in the email. What would be the complete code for the first html page, and what code do I put inside form of the second page to hold that information and pass it to the sendmail script?

tried an <input type="hidden" /> tag?
It works the same as a normal input field, only it isn't shown. Simply assign a name and value, and you can read them from the POST vars on the next page.