在线等,大量数据程序处理出现问题!!!

级登录</p></td>
<td width="14%" height="30"><div align="center">
<select name="class1" onChange="changeclass2();changeclass3();changeclass4()">
<option value="请选择" selected>请选择</option>
<%
set rs=server.CreateObject("adodb.recordset")
rs.open "aaa",conn,1,3
do while not rs.eof
%>
<option value="<%=rs("aname")%>"><%=rs("aname")%></option>
<%
rs.movenext
loop
%>
</select>
</div></td>
<td width="15%"><select name="class2" id="class2" onChange="changeclass3();changeclass4()">
<option value="请选择" selected>请选择</option>
</select>
</td>
<td width="15%"><select name="class3" id="class3" onChange="changeclass4()">
<option value="请选择" selected>请选择</option>
</select>
</td>
<td width="18%"><select name="class4" id="class4">
<option value="请选择" selected>请选择</option>
</select>
<%
set rs=server.CreateObject("adodb.recordset")
rs.open "bbb",conn,1,1
num=rs.recordcount
str=""
for i=1 to rs.recordcount
str=str&rs("bname")&"-"&rs("bname")&","
if rs.eof then exit for
rs.movenext
next
rs.close
rs.open "ccc",conn,1,1
num2=rs.recordcount
str2=""
for i=1 to rs.recordcount
str2=str2&rs("cccname")&"-"&rs("cccname")&","
if rs.eof then exit for
rs.movenext
next
rs.close
rs.open "ddd",conn,1,1
num3=rs.recordcount
str3=""
for i=1 to rs.recordcount
str3=str3&rs("cccname")&"-"&rs("cccname")&","
if rs.eof then exit for
rs.movenext
next
rs.close
%>
<script LANGUAGE="javascript">
arr="<%=str%>".split(",");
a=arr.length
ar=new Array()
for (i=0;i<a;i++){
ar[i]=arr[i].split("-");
}
onecount=ar.length;
arr2="<%=str2%>".split(",");
a2=arr2.length
ar2=new Array()
for (i=0;i<a2;i++){
ar2[i]=arr2[i].split("-");
}
onecount2=ar2.length;
arr3="<%=str3%>".split(",");
a3=arr3.length
ar3=new Array()
for (i=0;i<a3;i++){
ar3[i]=arr3[i].split("-");
}
onecount3=ar3.length;
function changeclass2() {
document.myform.class2.length=0
lid=myform.class1.value;
for (i=0;i<onecount;i++) {
if (ar[i][0] == lid) {
document.myform.class2.options.add(new Option(ar[i][1], ar[i][1]));
}
}
}
function changeclass3() {
document.myform.class3.length=0
lid2=myform.class2.value;
for (i=0;i<onecount2;i++) {
if (ar2[i][0] == lid2) {
document.myform.class3.options.add(new Option(ar2[i][1], ar2[i][1]));
}
}
}
function changeclass4() {
document.myform.class4.length=0
lid3=myform.class3.value;
for (i=0;i<onecount3;i++) {
if (ar3[i][0] == lid3) {
document.myform.class4.options.add(new Option(ar3[i][1], ar3[i][1]));
}
}
}


</script>
</td>
<td width="27%" bgcolor="#efefef"><input type="submit" name="Submit" value="dddd"></td>
</tr>
</form>



说明:aaa表中有40条数据,bbb表有400条数据,ccc表有4000,ddd表有40000条数据



程序每次运行都出现超时,请大家帮我解决这个问题,如何提高运算速度!!!