一个很简单的办法实现TD的加亮效果.

<script> 
function Menu_Init(obj){ 
var tds = obj.getElementsByTagName("td"); 
for (var i = 0; i < tds.length; i++) 
{ 
if (tds[i].className == "MenuOptions") 
{ 
tds[i].onmouseover = switch_bg; 
tds[i].onmouseout = switch_bg; 
} 
} 
} 
function switch_bg(e){ 
if (this.className=="MenuOptions_click") return 
this.className = (this.className == "MenuOptions") ? "MenuOptions_hilite" : "MenuOptions"; 
} 
</script> 
<style> 
.MenuOptions{ 
padding:2px; 
cursor:hand; 
color:#000000; 
} 
.MenuOptions_hilite{ 
padding:1px; 
border:outset 1px #669999; 
cursor:hand; 
color:#000000; 
} 
</style> 

<table id=MenuTools border="0" cellspacing="2" style="border:1px solid #000000;color:#000000;font-size:12px"> 
<tr> 
<td class="MenuOptions" >大家好呀 
<td class="MenuOptions" >很容易实现的效果 
<td class="MenuOptions" >喜欢的就拿去用吧 
<td >这个不允许加亮 
</tr> 
</table> 
<script>Menu_Init(MenuTools)</script> 
详细出处参考：http://www.jb51.net/article/217.htm