CoffeeScript to use with checkbox to hide / unhide form fields or div.

hide_unhide.coffee

# Use this if you only want to use the checkbox as a clicker
$('#checkbox-id').click ->
    $('.what-you-want-to-hide').slideToggle('slow')

# Use this if you actually care about checking to see if the checkbox has been checked
$('#checkbox-id').click ->
    if $(@).prop('checked')
      $('.what-you-want-to-hide, .what-you-want-to-hide-also').slideDown 'slow'
    else
      $('.what-you-want-to-hide, .what-you-want-to-hide-also').slideUp 'slow'

# This version creates a variable to use so that it's DRY
    # If you wish for this to persist in your Rails app, 
    # you also have to add an attr to the model.
    attr_accessor :checkbox-id
    # and, you have to have this line for simple form
    = f.input :checkbox-id, as: :boolean
    
fieldVisibility = ->
    if $('#checkbox-id').prop('checked')
      $('.what-you-want-to-hide').slideDown 'slow'
    else
      $('.what-you-want-to-hide').slideUp 'slow'

  $('#checkbox-id').click ->
    fieldVisibility()

  fieldVisibility()