jquery hiding/showing feild

gistfile1.txt

# my jquery specifics (jq_actions.js)

var $j = jQuery.noConflict();
var $extra_kinds = 'of <input id="indicator_number_name" name="indicator[number_name]" size="15" type="text" />'


$j(document).ready(function(){
  $j("#kinds").change(function(){
    var $value = $j('#indicator_kind').val();
    if ($value == "number")
      {
        $j('#extra').html($extra_kinds);
      }
    else
      {
        $j('#extra').html('');
      }
  });
});

# in my view 

<td id='kinds'><%= f.select :kind, options_for_select(['number', 'time', 'achieved']), :id => "test" %><div id="extra" /></td>