Select All Checkbox - Check or uncheck all checkboxes based on select-all checkbox. If individual checkboxes change update select-all checkbox accordingly.

sample Form

<input id="select-all" type="checkbox">
<input name="check-me" type="checkbox" value="check 1">
<input name="check-me" type="checkbox" value="check 2">
<input name="check-me" type="checkbox" value="check 3">
<input name="check-me" type="checkbox" value="check 4">
<input name="check-me" type="checkbox" value="check 5">
<input name="check-me" type="checkbox" value="check 6">
<input name="check-me" type="checkbox" value="check 7">

SelectAll

$('#select-all').on 'change', @onChangeSelectAll
$('input[name="check-me"]').on 'change', @onChangeCheckbox

onChangeSelectAll: (e) ->
  $('input[name="check-me"]').prop 'checked', $(e.target).prop('checked')
  
onChangeCheckbox: (e) ->
  selected = false
  number_selected = 0
  $('input[name="check-me"]').each ->
    if $(this).prop('checked')
      selected = true
      number_selected++
  $('#select-all').prop('checked', if number_selected is $('input[name="check-me"]').length then true else false)