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

<tr><td>   <p>     <b>Monday</b>     <%= f.check_box :monday %>     <%= observe_field(:monday_checked, :function => visual_effect('appear', 'monday-div')) %>     <%= observe_field(:monday_unchecked, :function => visual_effect('fade', 'monday-div')) %>   </p> <div id='monday-div'><div>   <p>     <b>Start</b><br />     <%= f.time_select :monday_start, :twelve_hour => true %>   </p>

  <p>     <b>End</b><br />     <%= f.time_select :monday_end, :twelve_hour => true %>   </p> </div></div>