高手请解决!!!

var i=document.all.ZiDuan.options[document.all.ZiDuan.selectedIndex].value;

解决方案 »

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function add()
    {
var i=document.all.ZiDuan.options[document.all.ZiDuan.selectedIndex].value;
var ziduan;             //声明一个变量
switch(i)
    {
case 1:
       ziduan="记录号 ";
           break;
case 2:
   ziduan="订货日期 ";
       break;
case 3:
   ziduan="采购员 ";
       break;
             }
        form.S1.value="select * from stock "+ziduan;
}
<html>
<head>
<script language="javaScript">
function add()
    {
var i=form.ZiDuan.value;
var ziduan;
switch(i)
    {
case 1:
       ziduan="记录号 ";
           break;
case 2:
   ziduan="订货日期 ";
       break;
case 3:
   ziduan="采购员 ";
       break;
             }
       form.S1.value=form.S1.value+ziduan;
</script>
</head>
<form name=form method=post>
<input type="button" value="添加条件" name="Add" onclick="add()">
</form>
</html>
form.ZiDuan.value  改成
--->document.form.ZiDuan.options[document.form.ZiDuan.seletedIndex].value
<html>
<head>
<script language="javaScript">
function add()
    {
var i=form.ZiDuan.options[form.ZiDuan.selectedIndex].value;
var ziduan;
switch(i)
    {
case "1":
       ziduan="记录号 ";
           break;
case "2":
   ziduan="订货日期 ";
       break;
case "3":
   ziduan="采购员 ";
       break;
            }
      // form.S1.value=form.S1.value+ziduan;
       alert(ziduan);

}
</script>
</head>
<form name=form method=post>
<select id="ZiDuan" size="1" name="ZiDuan">
<option value="1" selected>记录号</option>
<option value="2" selected>订货日期</option>
<option value="3" selected>采购员</option>
</select>
<input id="S1" type="hidden">
<input type="button" value="添加条件" name="Add" onclick="add()">
</form>
</html>
我太粗心了,把case 1改成case "1"就ok了,其它地方都可以不改