try<table cellspacing="0" cellpadding="0">
<tr>
<td onmouseover="this.style.backgroundColor='gray';" onmouseout="this.style.backgroundColor='';">hello world</td>
</tr>
</table>
<tr>
<td onmouseover="this.style.backgroundColor='gray';" onmouseout="this.style.backgroundColor='';">hello world</td>
</tr>
</table>
如a.link{font-color: red;}
a.active{font...}