麻烦大家修改下实例中的BUG？

兼容IE6,FF2<html>
<head>
<title>编辑表格</title>
<style type="text/css">
<!--
body { font-size:12px;}
input {
width:100%;
font-family: Geneva, Arial, Helvetica, sans-serif;
font-size: 12px;
color: #666;
background-color: #FFFFE1;
border: 1px solid #999;
}
.Table { border-width:1px 0px 0px 1px; border-style:solid; border-color:#999; border-collapse: collapse;}
.Table td { border-width:0px 1px 1px 0px; border-style:solid; border-color:#999;word-break:break-all;}
-->
</style>
<script type="text/javascript">
var oldObj=null;
var gTxt=document.createElement("input");//创建text文本框表单对象
gTxt.type="text";
function setEdit(evt){
var obj = evt.srcElement || evt.target;
if(!obj || obj.tagName.toUpperCase()!="TD" || obj==oldObj)
return ; if(oldObj)
{
var txtNode = document.createTextNode(gTxt.value);
gTxt.parentNode.appendChild(txtNode);
}
oldObj=obj;
gTxt.value = obj.childNodes[0].nodeValue;
for(var i=obj.childNodes.length-1;i>=0;i--)
obj.removeChild(obj.childNodes[i]);
obj.appendChild(gTxt);
gTxt.focus();
}
</script>
</head><body>
<table width="80%"  border="0" cellpadding="0" cellspacing="0" onclick="setEdit(event)" class="Table">
  <tr>
    <td width="17%">a</td>
    <td width="19%">bb</td>
    <td width="30%">asdf</td>
    <td width="23%">eee</td>
    <td width="11%">adsf</td>
  </tr>
  <tr>
    <td>1</td>
    <td>3</td>
    <td>4</td>
    <td>5</td>
    <td>9</td>
  </tr>
  <tr>
    <td>as</td>
    <td>asdfsdfa</td>
    <td>sadfsdaf</td>
    <td>sadfsdfa</td>
    <td>sdafsadf</td>
  </tr>
  <tr>
    <td>sadfsdfa</td>
    <td>asdf</td>
    <td>&nbsp;</td>
    <td>asdfasdf</td>
    <td>asdfasf</td>
  </tr>
  <tr>
    <td>asdfsadf</td>
    <td>asdfsadf</td>
    <td>asdfasdfasd</td>
    <td>ea</td>
    <td>asdfasfd</td>
  </tr>
</table>
</body>
</html>