调试易

http://www.cnblogs.com/goody9807/archive/2005/07/05/186602.html

var op = document.createElement("OPTION");
select .options.add(op);
op.innerText = temp;
op.value = i;

<script defer>
function fnc(){
re_name.value=r0.options[r0.selectedIndex].text
}function fncAdd(){
var txt=document.all.re_name.value;
if (txt.length>0 && r00.innerText=="")
{r00.innerHTML  += txt;
haha.style.display="none";}
}
</script><input type=text id=re_name style="width:95px;height:20px;font-size:10pt;" value="">
<span style="width:20px;border:0px solid red;">
    <select id="r0" style="margin-left:-100px;width:118px; background-color:#FFEEEE;" 
                       onChange="fnc();">
        
        <option value="1" id="r01">111111</option> 
        <option value="2" id="r02">222222</option> 
        <option value="3" id="r03">333333</option>
        <option value="0" id="r00"></option>
    </select> 
</span> 
<span id=haha><input type="button" value="add a new" onclick="fncAdd();"></span>

var item=document.createElement("option");
item.text="fdsafdsa";
slts.add(item);