调试易

在刷新前,把相关的信息存在text里面.
不知道你的树是什么样子的啊?
只能是提供一种思路.<script>
//用input记录所选,防止刷新,后退后数据还原.
/* Start */
window.onbeforeunload=function()
{
    document.all.leftopt.value = document.all.left.outerHTML;
document.all.rightopt.value = document.all.right.outerHTML;
}
window.onload=function()
{
    if(document.all.leftopt.value!="")document.all.left.outerHTML=document.all.leftopt.value;
if(document.all.rightopt.value!="")document.all.right.outerHTML=document.all.rightopt.value;
}
/* End */
function addopt(locs,mylocs)
{
    for(var i = 0;i<locs.options.length;i++)
{
    var opt = locs.options[i];
if(opt.selected)
{
    var flag = true;
for(var j = 0;j<mylocs.options.length;j++)
{
    var myopt = mylocs.options[j];
if(opt.value == myopt.value)
{
    flag = false;
}
}
if(flag)
{
   locs.options[i] = null;
   mylocs.options[mylocs.options.length] = new Option(opt.text,opt.value,true,true)
}
}
}
}
</script>
<table> 
        <TR> 
        <td><b> 选择节点组 </b></td> 
        <td> 
                     <table> 
                     <tbody> 
                     <TR> 
                     <TD> 
                     <SELECT multiple name=left size=8 style="width:100"> 
                       <option value=1>1 
                       <option value=2>2 
                       <option value=3>3 
                       <option value=4>4 
                     </SELECT> 
                     </TD> 
                    <TD> 
                    <INPUT onclick=addopt(document.all.left,document.all.right) type=button value=添加> 
                    <BR><BR> 
                    <INPUT onclick=addopt(document.all.right,document.all.left) type=button value=删除> 
                    </TD> 
                    <TD> 
                    <P> 
                     <SELECT multiple name=right size=8 style="width:100"> 
                    </SELECT> 
                    </P> 
                    </TD> 
                    </TR> 
                    </TBODY> 
                    </TABLE> 
        </td> 
</tr> 
</table> 
<input type=hidden name=leftopt>
<input type=hidden name=rightopt>