mycode.js

jQuery ->
  $('#counselor_supervisor_employee_position_id').hide()
  position = $('#counselor_supervisor_employee_position_id').html()
  $('#counselor_supervisor_employee_department_id').change ->
    department = $('#counselor_supervisor_employee_department_id :selected').text()
    escaped_department = department.replace(/([ #;&,.+*~\':"!^$[\]()=>|\/@])/g, '\\$1')
    options = $(position).filter("optgroup[label='#{escaped_department}']").html()
    if options
      $('#counselor_supervisor_employee_position_id').html(options)
      $('#counselor_supervisor_employee_position_id').show()
    else
      $('#counselor_supervisor_employee_position_id').empty()
      $('#counselor_supervisor_employee_position_id').hide()