跪求一textarea事件,选择下拉列表后的值在textarea里即时显示!
一个三级联动菜单.第一级第二级第三级依次选择,最关心的是第三级的内容.我想把第三级的内容即时显示在textarea中,请问用什么事件处理?谢谢!
部分代码如下:(用java做的三级联动菜单^^)

    <form   onsubmit= "return(confirm( '确认提交吗？ ')) "   name= "myform "   method= "post "   action= "do_sqzx.asp ">
   
    <div   align= "center ">
    <table   bgcolor= "#0099cc "   width= "768 "   cellspacing= "0 "   cellpadding= "0 ">
    <tr>
        <td   width= "100% "   align= "center "   bgcolor= "#FFFFFF "> <span   class= "STYLE2 "> 车辆故障描述 </span> </td>
    </tr>
    <tr>
        <td> <table   bgcolor= "#0099cc "   width= "768 "     cellspacing= "0 "   cellpadding= "0 ">
    <tr>
                <td   width= "29% "   nowrap= "nowrap "> 大   类
<select   name= "s1 "   onChange= "changelocation(document.myform.s1.options[document.myform.s1.selectedIndex].value) ">
    <option   selected= "selected "> --请选择大类-- </option>
<%
sql1   =   "select   *   from   a   order   by   dalei_mc   asc "  
set   rs1   =   cn.Execute   (sql1)  
do   while   not   rs1.eof  
%>  
<option   value= " <%=trim(rs1( "a_id "))%> "> <%=trim(rs1( "dalei_mc "))%> </option>
<%  
rs1.movenext  
loop
rs1.close  
set   rs1   =   nothing  
cn.Close  
set   conn   =   nothing  
%>  
</select> </td>

<td   width= "36% "   align= "left "> 总成名称
<select   name= "s2 "   onchange= "changelocation2(document.myform.s2.options[document.myform.s2.selectedIndex].value) ">
    <option   selected= "selected "   value= " "> --请选择总成名称-- </option>
</select> </td>
   
   
    <td> 故障描述
<select   name= "s3 ">  
<option   selected= "selected "> --请选择故障描述-- </option>  
</select> </td>

</tr>
  <tr> <td   colspan= "3 "> <textarea     name= "gz_meno "   cols= "50 "   rows= "5 "> </textarea>

------解决方案--------------------
<select name= "s3 " onchange= "InsertTxt() ">

<script>
function InsertTxt()
{
if (document.myform.s3.selectedIndex!=0)
{
document.myform.gz_meno.value = " ";
document.myform.gz_meno.value=document.myform.s3.options[document.myform.s3.selectedIndex].value;
}
}
</script>
------解决方案--------------------
document.myform.s3.options[document.myform.s3.sel