_tasks_body.html.erb

<% content_for :modal_partials do %>
  <%= render :partial => "/admin/tasks/edit_task_modal", :locals => {:task => t} %>
  <%= render :partial => "/admin/tasks/delete_task_modal", :locals => {:task => t} %>
<% end %>

<%# content_for :pre_body_close do
  <script>
    alert('hej')
    $(".completed").live("change", function(el) {
      $.ajax({
        url: "/admin/tasks/completed",
        beforeSend: function() { alert("Hi"+el) },
        data: "id="+el, 
        success: function() { alert('Bye') }
      });
    });
  </script>
end %>

<tr>
  <td>
    <%= check_box_tag "completed", t.id, t.completed, :class => "completed" %>
  </td>
  <td><%= t.task_type %></td>
  <td><%= link_to "#{truncate(t.subject, :length => 20)}", admin_task_path(t) %></td>
  <td><%= t.responsible(&:name) %></td>
  <td><%= link_to t.client, admin_client_path(t.client) unless t.client.nil? %></td>
  <td><%= t.deadline.strftime("%d/%m/%y %H:%M") %></td>
  <td><%= t.author(&:name) %></td>
  <td>
    <a data-toggle="modal" href="#editTask<%= t.id %>"><%= image_tag "edit.png" %></a>
    <a data-toggle="modal" href="#deleteTask<%= t.id %>"><%= image_tag "delete.png" %></a>
  </td>
</tr>

custom.js

$(".completed").live("change", function(e) {
      var data = "id=" + this.value;
      var url = '/admin/tasks/completed' // + (this.checked ? 'completed' : 'uncompleted');
      $.ajax({
        type: 'POST',
        url: url,
        data: data, 
        beforeSend: function() { console.log(this,e) },
        success: function() { alert('All done.') }
      });
    });  

routes.erb

resources "tasks" do
      collection do
        post 'completed'
      end
    end

tasks_controller.rb

def completed
    @task = Task.find(params[:id])
    @task.toggle! :complete
    
    render :nothing => true
      #if @task.completed != true
        #@task.completed = true
        #@task.update_attributes :completed, true
      #else 
        #@task.completed = false
        #@task.update_attributes :completed, false
      #end
      #@task.save    
    
  end

Started POST "/admin/tasks/4/completed" for 127.0.0.1 at 2012-04-27 11:46:55 +0200
Processing by Admin::TasksController#completed as /
Parameters: {"id"=>"4"}
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 LIMIT 1
Task Load (0.2ms) SELECT "tasks".* FROM "tasks" WHERE "tasks"."id" = ? LIMIT 1 [["id", "4"]]
Completed 500 Internal Server Error in 3ms

NoMethodError (undefined method complete?' for #<Task:0x007fe5e7dc1cc8>): app/controllers/admin/tasks_controller.rb:71:incompleted'

Rendered /Users/znowm4n/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/gems/1.9.1/gems/actionpack-3.2.3/lib/action_dispatch/middleware/templates/rescues/_trace.erb (2.2ms)
Rendered /Users/znowm4n/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/gems/1.9.1/gems/actionpack-3.2.3/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (0.8ms)
Rendered /Users/znowm4n/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/gems/1.9.1/gems/actionpack-3.2.3/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (9.1ms)