js控制表格隔行变色

只是加载时候隔行变一个颜色，鼠标滑动上去时候没有变化

<table width="800" border="0" cellpadding="0" cellspacing="0">

<tr>

<td>不变色</td>

</tr>

<tbody id="goaler">

<tr>

<td>xxxxxxxx</td>

</tr>

<tr>

<td>xxxxxxxx</td>

</tr>

<tr>

<td>xxxxxxxx</td>

</tr>

<tr>

<td>xxxxxxxx</td>

</tr>

</tbody>

<tr>

<td>不变色</td>

</tr>

</table>

<script language="JavaScript">

<!--

var TbRow = document.getElementById("goaler");

if (TbRow != null)

{

for (var i=0;i<TbRow.rows.length ;i++ )

{

if (TbRow.rows[i].rowIndex%2==1)

{

TbRow.rows[i].style.backgroundColor="";

}

else

{

TbRow.rows[i].style.backgroundColor="#F1F1F1";

}

}

}

//-->

</script>