XF 2.1 How to pre-populate Contact Form from button link?

[bzcomputers]

Trying to populate the subject and message portions of the contact form from a button link. This is what I'm attempting and it is not working...

onClick="window.open('//www.mysite.com/community/misc/contact?Subject=Test%20Subject&Message=Test%20Message.','_blank')"

Is it possible to do this without creating a custom add-on?

Alternative is to use a "mailto:" link but this leaves a site email address out there in the code for scrapers and the return message will not contain user name/id and ip info. Definitely not the preferred method.

 

[bzcomputers]

Anyone have an ideas on how to extend the current contact form to allow query strings like above?