anchor.diff:                      # <http://stackoverflow.com/questions/12325066/button-click-event-fires-when-pressing-enter-key-in-different-input-no-forms>
                 }
               ]
  -            div {}, bind ->
  +            div bind ->
                 if tasks.length() == 0
                   []
                 else
  
positive.code:         $('body').prepend(
            section {id: 'todoapp'}, [
              header {id: 'header'}, [
                h1 {}, ['todos']
                input {
                  id: 'new-todo'
                  type: 'text'
                  placeholder: 'What needs to be done?'
                  autofocus: true
                  init: -> @keydown (e) =>
                    if e.which == 13
                      tasks.push(new Task(@val().trim()))
                      @val('')
  
negative.code:                     input {
                        id: 'toggle-all'
                        type: 'checkbox'
                        change: ->
                          for task in tasks.all()
                            task.isCompleted.set(@is(':checked'))
                      }
                      label {for: 'toggle-all'}, 'Mark all as complete'
                      ul {id: 'todo-list'}, tasks.map (task) ->
                        editBox = null
                        li {
  