rails 3, how add a simple confirmation dialog when user clicks a link

Question

what is the easiest way in rails 3 to to ask "Are you sure you want to do that?" when the user clicks on a link?

the link in this case overwrites some data with a new value. It's a simple link_to (GET) back to the same controller method, with a param[] added.

Answer 1

EDIT:
<%= link_to "Do something", {:controller => "foo", :action => "bar"}, :confirm => "Are you sure you want to do that?" %>