IE下面很好写，firefox下试了几种写法都不行，比如
var oOption = document.createElement("OPTION");
oOption.setAttribute("text",fromObj.options[sIndex].text);
oOption.setAttribute("value",fromObj.options[sIndex].value);
selectObj.add(oOption);
或者
selectObj.options.add(oOption);
最后终于找出来了，要这么写
myOption=document.getElementsByTagName('select')[0];
myOption.options[myOption.options.length]=new Option('newText','newValue');
想在两个select之间倒option，全部代码如下：
<script type="text/javascript">
function move(from){
var fromObj,toObj;
if(from == "toRight"){
fromObj = document.getElementsByName("leftSelect")[0];
toObj = document.getElementsByName("rightSelect")[0];
}else{
fromObj = document.getElementsByName("rightSelect")[0];
toObj = document.getElementsByName("leftSelect")[0];
}
var sIndex = fromObj.selectedIndex;
if(sIndex < 0){alert("请选择符合性要求!");return;};
toObj.options[toObj.options.length]=new Option(fromObj.options[sIndex].text,fromObj.options[sIndex].value);
fromObj.remove(sIndex);
}
</script>
<body>
<table>
<tr>
<td>
<select name="leftSelect" size="10">
<option value="1">COSO</option>
<option value="2">Cobit</option>
<option value="3">ITIL/ISO20000</option>
<option value="4">CMMI</option>
<option value="5">PRINCE2</option>
<option value="6">银监会313号文</option>
</select>
</td>
<td>
<input value=">" type="button" onclick="move('toRight')"><br/>
<input value="<" type="button" onclick="move('toLeft')">
</td>
<td>
<select name="rightSelect" size="10">
<option value="7">等级保护</option>
<option value="8">BS7799/ISO27000</option>
</select>
</td>
</tr>
</table>
</body>