If your placing the support-image-button.js.aspx file on the site what should be put in the url?  ?input_department=sales

I have tried this and it doesn't work.  I don't see the querystring being passed along.  Do I have to make changes to both the support-image-button.js.aspx and supportredirect.asps files?  I to have different departments that want the default department to show there department. Thanks in advance for the help.