Visual_effect check_box

Am I even close on how to do this? I’ve googled alot and still can;t
get this to work

Monday <%= f.check_box :monday %> <%= observe_field(:monday_checked, :function => visual_effect('appear', 'monday-div')) %> <%= observe_field(:monday_unchecked, :function => visual_effect('fade', 'monday-div')) %>

Start
<%= f.time_select :monday_start, :twelve_hour => true %>

End
<%= f.time_select :monday_end, :twelve_hour => true %>