Question

Have been using a simple CSS only tooltip.

Working Example
css:

.tip
{
    position:relative;
}
.tip span.tooltip
{
    display:none;
    background:#ff5112;
    border:1px solid #9C0;
}
.tip:hover span.tooltip
{
    display:block;
    position:absolute;
    top:2em; left:2em; width:15em;
    border:1px solid #0cf;
    background-color:#cff; color:#000;
    text-align: center
}

html:

<span class="tip">
<table><tr>
<td>Working Tip</td><span class="tooltip">Tip</span>  
</tr></table>
</span>

Not working example:
html:

<table><tr>
<span class="tip"><td>Not working TIP</td><span class="tooltip">Tip</span></span>
</tr></table>

And a Live example

Answer 1

Your problem is the table element – you cannot have a span that wraps <td>. Get rid of the table and everything will work.