求助:javascript 中变色的实现

Question

<table width="100%"  border="0" cellspacing="0" cellpadding="0">
  <tr>
   <td bgcolor="#336699" onmouseover="this.style.backgroundColor='#f0f0f0';a.style.color='#003399'" onmouseout="this.style.backgroundColor='';a.style.color=''"><a href="#" id=a>新闻</a></td>
  </tr>
</table>

Answer 1

<table width="100%"  border="0" cellspacing="0" cellpadding="0">
  <tr>
   <td bgcolor="#336699" onmouseover="overbao(this)"
                    onmouseout="outbao(this)"><a href="#" ><font color="#FFFFFF">新闻</font></a></td>
  </tr>
</table>
<script>
function overbao(obj)
{
    obj.style.backgroundColor='#f0f0f0'
    obj.firstChild.firstChild.color='#003399'
}
function outbao(obj)
{
    obj.style.backgroundColor=''
    obj.firstChild.color=''
}
</script>