Shared error messages for ruby on rails. Replace @user with relevant variable. Also change the css classes and such to match the app you use it on.

_error_messages.html.erb

<% if @user.errors.any? %>
  <div id="error_explanation" >                                             
    <div class="alert alert-error">
      The form contains <%= pluralize(@user.errors.count, "error") %>.      
    </div>
    <ul>
      <% @user.errors.full_messages.each do |msg| %>                        
        <li>* <%= msg %></li></br>                                          
      <% end %>
    </ul> 
      
  </div>
  <% end %>