popup not scrolling

I made a popup with this code:

<%=link_to 'Rules', {:action => 'rules', :id => @promotion.id}, :popup
=> ['ruling_box', 'height=300,width=600'] if @promotion.is_contest? %>

But it's not scrolling to the content. What should I add to it?

You need to add an :anchor into the url_for part of your link_to call.

{:action => 'rules', :id => @promotion.id, :anchor => 'foo' }

http://api.rubyonrails.com/classes/ActionView/Helpers/UrlHelper.html#M000912