Hide a submit_tag in Rails 2.3 by default

Question

I wanted to have the submit_tag in rails 2.3 hidden by default i.e. get style="visibility:hidden" in the html output for the submit_tag. I searched the APIs but wasn't of any help. I tried sth. like

<%= submit_tag 'Save', :id=>"submitBtn"+i.to_s, :visibility=>"hidden"%>

just in case hoping that it might work. But it didn't work. :-(