gistfile1.txt

Tanga.initialize '#upsell', ->
  select = $('#upsell select')
  notice = $('#upsell p.notice')

  // more readable checkbox selector
  checkbox = $('#upsell :checkbox')

  callback = ->
    // Let's only check the value of $(this), easier to debug if there is more than one checkbox.
    notice.toggle $(this).is(":checked")

    // select is a jQuery element, use jQuery methods to disable it.
    if $(this).is(":checked")
      select.attr("disabled", 'disabled')
    else
      select.removeAttr("disabled")
    
    true

  // removing this, the value gets set when you trigger the change() event
  // select.disabled = true

  // bind the callback and trigger it.
  checkbox.change(callback).change()