更改选项长度后，将选项选择为默认

Question

I got two radio button that are yes and no , so if i click on yes the tr of div1 that is radio button of dealer and consumer will show from hide, whereas if i click on no it will not show up the two radio button as i just mention.

So now the condition is when i click on yes and click on dealer radio button the select option of CATEGORY have to change to different value as i coded in function override of javascript and also different value if i click on consumer radio button.

BUT if i click on No radio button i wanted to set the CATEGORY select option to default value as i coded in vbscript.

Let's say i clicked yes and consumer radio button the onchange function change the option length to 1 so after that if i click back on No radio button ,the select option CANNOT change back to the default value anymore.

Any solutions for this? Hope help and thank you.

<script language="Javascript">
function Override(value){
    var list = document.getElementById("selCATE");
    if (value == "1"){
        document.getElementById('selCATE').options.length = 1;
        list.add(new Option("Gift to consumers without proof of package sales","Gift to consumers without proof of package sales"));
        list.add(new Option("Gift to consumers without proof of package sales","Gift to consumers without proof of package sales"));
    }else if (value == "2"){
        document.getElementById('selCATE').options.length = 1;
        list.add(new Option("Gift to dealers","Gift to dealers"));
    }
}
   </script>

<input name="rdoGFLG" type="radio"  value="Y" onchange=""/>Yes
<input name="rdoGFLG" type="radio"  value="N" onchange="Override(this.value)"/>No

<tr id="div1">
    <td>
        <input name="rdoGTYP" id="rdoGTYP" type="radio" value="1"  onchange="Override(this.value);">Consumer
        <input name="rdoGTYP" id="rdoGTYP" type="radio" value="2" onchange="Override(this.value);">Dealer   
    </td>
</tr>

<td valign="top"><b>Category</b></td>
<td valign="top">:</td>
        <%
        objADO.openRecordSet
        strSQL = "SELECT catc from cogstc  a where cono='" & SQLEncode(StrCono) & "' and acti=1 order by posi "
        Set objRS= objADO.runQuery(StrSQL)

        if objRS.recordCount > 0 then
            Response.write "<td valign='top' align='left' width='50%'><select name='selCATE' class='NormalInputTextField'>"
            Response.write "<option value=''>Select One</option>"

            Do until objRS.EOF
                Response.write "<option value='" & objRS("catc") & "'>" & objRS("catc") & "</option>"
                objRS.MoveNext
            loop
        Response.write "</select></td>"
        end if
%>  

Answer 1

Try placing a

list.selectedIndex=0;

where you want the list to return to default. The index is 0 based so the first element is 0 not 1. 1 is the second element. You can change 0 to -1 (negative one) if you want the list to select nothing.