Can I use a field ID as the emails subject line?

Design help Custom code
1

Hey guys!

I’m working on a directory database for a small niche, I want collection pages for each company to have a contact form that reaches them directly. My thoughts are:

Pull Collection Data (Email Address) to Hidden Field In Form
Send form data to a gmail account.
Use email address as the recipient address via forwarding.

I’m using the following script (provided by cyberdave and a little modification :D) to pull collection data (an email address) to a hidden field in a form (on the dynamic page):

<script type="text/javascript" language="JavaScript">
<!--
document.write('<input ');
document.write('   type="hidden" ');
document.write('   name="sendto" ');
document.write('   value="**DYNAMICFIELDHERE**"');
//-->
</script>

Which is working great. Now I need to use that dynamic data. I understand that gmail offers email forwarding based on the subject line. But I’m starting to fear this is not possible with webflow. If not, any ideas?