create an array or split a long string seperated by tabs newlines carriage returns and commas.

EG

emails = "skdjf@sdklfj.com sdflj@kj.com sldfj@klj.com, slkj@kjl.com,lskjdf@lkj.com, \r\nlkjkjl@kjk.com"

becomes

=> ["skdjf@sdklfj.com", "sdflj@kj.com", "sldfj@klj.com", "slkj@kjl.comlskjdf@lkj.com", "lkjkjl@kjk.com"]

emails = emails.split(/,/).join().split()

// hide all digits of a credit card number except the last 4. eg<br/>
// cc = "12345678901123456"
// hide_card_number(cc)
// [ "************3456" ]

  def hide_card_number(card_number)
    size = card_number.to_s.size - 1
    cc = "" 
    i = 0
    0.upto(size) do 
      if( i > size - 4 )
      else
        cc += "*" 
      end
      i += 1
    end
    cc = cc + card_number[size-3, size].to_s
    return cc 
  end

Ajax radio buttons. update the page div when a radio button is pressed.

<div id="join">
        <p class="title">
      Sign-up
        </p>
   <% form_for :radio_join, :html => { :id => 'radio_join' } do %>
      <%= radio_button_tag :join_page, :member %> Member
      <%= radio_button_tag :join_page, :model %> Model
      <%= radio_button_tag :join_page, :photographer %> Photographer
    <% end -%>
<% form_for :user, @user, :url => {:action => 'save_free'} do |user_form| -%>
        <div class="info">
    <%= render :partial => 'common/user_form', :object => user_form %>
                <p class="alignright">
        <%= submit_tag 'JOIN', :class => 'inputSubmit' %>
                </p>
      <br />
      <br />
        </div>
  <% end -%>

     </div>
<%= observe_form :radio_join, :url => { :action => 'choose_page' }, :update => "join", :complete => "Element.show('join')", :frequency => "0.25" %>