Albert Khasky

Without having to create my own form and use the API, is it possible to set the value of a hidden custom field based on a url param? I'd like it to be a private/agent only field, but given the responses above, it seems unlikely. As a possible workaround, could I stick some custom js that sets the value and hides that particular field? I'm using the Copenhagen theme. 

Any guidance would be most appreciated.

Thanks in advance!