When will <td valign="top"> not work?

Question

Have you ever concluded about this?

Now I've met one, very strange, don't know why.

My code:

<td valign="top">
    <input type="text" />
    <iframe scrolling="no" height="21px" frameborder="0" width="62px" marginheight="0" marginwidth="0" src="Server/SecCode.php">
    </iframe>
</td>

But it turns out to be that the "input" is valigned to the bottom,while "iframe" to the top.

Answer 1

I experienced something similiar, when I added the css code

<td style=" vertical-align: top;" >

manually within the td tag it corrected the problem for me.