javascript怎么修改table值

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<table id='mytable'>

<tbody>

<tr>

<td id='mytd'>这里是td的值</td>

</tr>

</tbody>

</table>

<br />

<input type='button' value='绝对路径获取td的值' οnclick='getTdDirectly()' />

<script>

function getTdDirectly(){

var tdobj = document.getElementById('mytd');

tdobj.innerText = "ssss";

}

</script>

</pre><pre name="code" class="html">