link

link to css

stylesheet_link_tag   'test'

test.css is in /public /stylesheets

link to image

image_tag  'test.jpg'

test.jpg is in  /public/images

link to page

link_to  "go to" ,  :controller=>"test", :action=>"index"

link to javascript:

javascript_indclude_tag  :defaults

link to prototype, effects, dragdrop, controls, application in /public/javascripts

url_for:

generate url according to route.rb

ex:

url_for ( :controller=>"rabbit", :action=>jump )

-->  http://localhost:3000/rabbit/jump