Desperate for a little html / cgi help --

[tzikeh]

I'm trying to figure out how to make a form field entry become a hidden input value. Anyone who knows anything about html forms and a little cgi, please read:
I have a form which includes the following hidden input value:

<INPUT name="mailfrom" type="hidden" value="Network Chicago - Contact Form">

So that when the form data is submitted, the "from" in the email says "Network Chicago - Contact Form".

What I would *like* the "from" to be is the person's email - which they are putting into the form itself in a field defined thusly -

<INPUT name="email" type="text" size="30">

I would like to somehow make this:

<INPUT name="mailfrom" type="hidden" value="xxx">

where "xxx" equals the value input to the "email" form field.

If anyone can figure this out and can explain it to me - PLEASE HELP.

Many, many thanks.