1. button_to_function(button_value, *args, ∓block)
   Returns a button that‘ll trigger a JavaScript function using the onclick handler. All of these go into the body tag of the view file. You can use the visual_effect function to specify any visual effects

2. Example :
   This will show a button with the value “Greeting”, upon clicking will show a alert box with “Hello World!” inside.

   <%=button_to_function "Greeting", "alert('Hello world!')" %>

   This will display a button with value “Fade”, upon clicking will fade in or fade out the element ‘fade_text’ (It can be a div element with id=fade_text).

   <%=button_to_function "Fade", visual_effect(:toggle_appear, "fade_text", :duration => 0.5)%>

3. link_to_function(name, *args, &block)
   Intead of a button, if you want to implement AJAX functionality using a text link. You can use this helper.
   Returns a link that will trigger a JavaScript function using the onclick handler and return false after the fact.

   Example :
   This will show a “Greeting” link, upon clicking will show a alert box with “Hello World!” inside.

   <%=link_to_function "Greeting", "alert('Hello world!')" %>

   This will display a “Slide Me” link, upon clicking it will slide in or out the element ’slide_text’ (It can be a div element with id=slide_text).

   <%=link_to_function "Slide Me", visual_effect(:toggle_slide, "slide_text", :duration => 0.5)%>

   Helper for Animation

4. visual_effect(name, element_id = false, js_options = {})
   Returns a JavaScript snippet to be used on the Ajax callbacks for starting visual effects.

   Example :
   This will show a “Highlight” button, upon clicking will highlight the element which is specified.

   <%=button_to_function "Highlight", visual_effect(:highlight, "element_id_name",:startcolor => '#ffff99', :endcolor => '#ffffff')%>

   This will display a “Grow” link, upon clicking it will grow the specified element_id_name

   <%= link_to_function "Grow", visual_effect(:grow,"element_id_name",:direction => "center",:duration => 1)%>

I would really suggest to go through Script.aculo.us WIKI to know more about every effect and their parameters. All of these effects can be used with RoR. For Example I have attached the code for the demo file.

Code for the Demo File

View Demo