ASP三级联动下拉菜单选择只有一级的确显示第三级，求修改!!!

比如我先选择了一个有第二级和第三级的选项后再选择一个只有一级的选项确第三级还是显示刚刚选择过得第三级，没有清空，请问怎么样清空，求添加代码？本人初学者


<%dim count
set rs=server.createobject("adodb.recordset")
rs.open "select * from [class_menu] order by class_order ASC",conn,1,1%>
<script language = "JavaScript">
var onecount;
onecount=0;
subcat = new Array();
<%
   count = 0
   do while not rs.eof
%>
subcat[<%=count%>] = new Array("<%=trim(rs("class_name"))%>","<%= rs("id")%>","<%=rs("class_id_1")%>");
<%
        count = count + 1
        rs.movenext
        loop
        rs.close
%>

onecount=<%=count%>;
function changelocation(locationid)
    {
    document.myform.class2id.length = 0;
    var locationid=locationid;
    var i;
    for (i=0;i < onecount; i++)
        {
            if (subcat[i][2] == locationid)
            {
             document.myform.class2id.options[document.myform.class2id.length] = new Option(subcat[i][0], subcat[i][1]);

    changelocation2(document.myform.class2id.options[document.myform.class2id.selectedIndex].value)
   }
        }


    }

function changelocation2(locationid)
    {
    document.myform.class3id.length = 0;
    var locationid=locationid;
    var i;
    for (i=0;i < onecount; i++)
        {
            if (subcat[i][2] == locationid)
            {
             document.myform.class3id.options[document.myform.class3id.length] = new Option(subcat[i][0], subcat[i][1]);
            }
        }

    }

</script>

<script language="JavaScript">
function CheckForm()
{

if(document.myform.class1id.value<=0) {
document.myform.class1id.focus();
    alert("请选择市级分类！");
return false;
  }

if(document.myform.class2id.value<=0) {
document.myform.class2id.focus();
    alert("请选择地区分类！");
return false;
  }

}

</script>

</head>
<body>

    <form name="myform" method="post" action="product_save.asp?action=add" onSubmit="return CheckForm();" enctype="multipart/form-data">
      <table width="70%" border="0" align="center" cellpadding="0" cellspacing="0">
        <tr>
          <td height="35" align="center" class="14p"><strong>选择分类</strong></td>
        </tr>
      </table>
      <table width="70%" border="0" align="center" cellpadding="0" cellspacing="0">
        <tr>
          <td height="22"> </td>
        </tr>
      </table>
        <table width="70%" border="0" align="center" cellpadding="3" cellspacing="0">



          <tr>
            <td align="center">
  <%
    rs.open "select * from [class_menu] where class_id_1='0' order by class_order ASC",conn,1,1
if rs.eof and rs.bof then
response.write "请先添加栏目。"
response.end
else
%>
              市区分类:
              <select name="class1id" size="1" id="class1id" onChange="changelocation(document.myform.class1id.options[document.myform.class1id.selectedIndex].value)" class="wenbenkuang">
                <option selected>选择市级分类</option>
                <option value="<%=rs("id")%>"><%=trim(rs("class_name"))%></option>
  <%
        dim selclass
        selclass=rs("id")
        rs.movenext
        do while not rs.eof
%>
                <option value="<%=rs("id")%>"><%=trim(rs("class_name"))%></option>
                <%
        rs.movenext
        loop
end if
        rs.close
%>
              </select>
              地区分类:
              <select name="class2id" size="1" id="class2id" onChange="changelocation2(document.myform.class2id.options[document.myform.class2id.selectedIndex].value)" class="wenbenkuang">
                <option selected>选择地区分类</option>
              </select>

              县级分类:
              <select name="class3id" class="wenbenkuang">
                <option selected>选择县级分类</option>
              </select>
  <SCRIPT language=JavaScript type=text/JavaScript>
for(i=0;i<document.myform.class1id.length;i++)
{
if(document.myform.class1id.options[i].value==<%=class1id%>)
    {
        document.myform.class1id.options[i].selected = true;
    }
}
changelocation(document.myform.class1id.options[document.myform.class1id.selectedIndex].value);
for(i=0;i<document.myform.class2id.length;i++)
{
if(document.myform.class2id.options[i].value==<%=class2id%>)
    {
        document.myform.class2id.options[i].selected = true;
    }
}
changelocation2(document.myform.class2id.options[document.myform.class2id.selectedIndex].value);
for(i=0;i<document.myform.class3id.length;i++)
{
if(document.myform.class3id.options[i].value==<%=class3id%>)
    {
        document.myform.class3id.options[i].selected = true;
    }
}

</SCRIPT>            </td>
          </tr>

      </table>
</form>
</TD>
</TR>
    <TR>
      <TD class=forumrow>
      </TD>
    </TR>

</TABLE>
<br>

<br>
</body>
</html>

3 个解决方案

#1

哪位大神，跪求如何修改？？？小弟在线等。。。

#2

每次选择一级的时候清空2,3级的项在判断是否有子项，有再添加

function changelocation(locationid)
    {
    document.myform.class2id.length = 0;

    document.myform.class3id.length = 0;/////////////
    var locationid=locationid;
    var i;
    for (i=0;i < onecount; i++)
        {
            if (subcat[i][2] == locationid)
            {
             document.myform.class2id.options[document.myform.class2id.length] = new Option(subcat[i][0], subcat[i][1]);

    changelocation2(document.myform.class2id.options[document.myform.class2id.selectedIndex].value)
   }
        }


    }

#3

谢谢版主。真的可以了。。。灰常灰常感谢。。

#1

哪位大神，跪求如何修改？？？小弟在线等。。。

#2

#3

谢谢版主。真的可以了。。。灰常灰常感谢。。

秒客网

ASP三级联动下拉菜单选择只有一级的确显示第三级，求修改!!!

3 个解决方案

#1

#2

#3

#1

#2

#3

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