how to update a single table cell using ajax

I'm trying to update a table cell based upon a selection in another cell
identified as "descPlaceholder". However, instead of getting the
intended cell updated the updated string gets displayed completely
outside of the table in a seemingly arbitrary spot on the form.

The form:

<table>
  <tr>
    <th>Code</th>
    <th>Name</th>
    <th>Quantity</th>
  </tr>
  <tr>
      <td>
        <%= select_tag :partcode,
          options_from_collection_for_select(@parts, 'id', 'code')
        %>
        <%= observe_field(:partcode,
          :update => :descPlaceholder,
          :url => {:action => :getPartName})
        %>
      </td>
      <div id="descPlaceholder">
        <td>placeholder for description</td>
      </div>
      <td>
        <%= text_field "partquantity", "quantity", :size =>5, :maxlength
=>5 %>
      </td>
  </tr>
</table>

getPartName.html.erb:
<td>Test Description</td>

getPartName method:
def
end

That'll never work because it's not valid HTML; a DIV can't be a child
of a TR.

You can alwaus just do the following:

<td id="descPlaceholder">

Eric Yen wrote:

You can alwaus just do the following:

<td id="descPlaceholder">

Wow, many thanks to both of you!