asp+ajax和数据库驱动的二级联动菜单

<%@language="vbscript" codepage="936"%>

<%
response.charset="gb2312"
bigclassid=safe(request.querystring("bigclassid"))
if bigclassid<>"" then
set re=new regexp
re.ignorecase=true
re.global=false
re.pattern = "^[0-9]{1,3}$"
if not re.test(bigclassid) then
response.write "非法参数"
response.end
end if%>

<%on error resume next
set p = conn.execute("select * from smallclass where bigclassid=" & bigclassid)
if err then
err.clear
response.write "查询出错"
response.end
end if
if not p.eof then
html = ""&vbnewline
do while not p.eof
html = html&""&p("smallclassname")&""&vbnewline
p.movenext
loop
html = html&""
else
html = "暂无小类"
end if
p.close
set p = nothing
conn.close
set conn = nothing
response.write html
html = ""
end if
%>
// JavaScript Document
function createxmlhttp()
{
xmlhttpobj = false;
try{
xmlhttpobj = new XMLHttpRequest;
}catch(e){
try{
xmlhttpobj=new ActiveXObject("MSXML2.XMLHTTP");
}catch(e2){
try{
xmlhttpobj=new ActiveXObject("Microsoft.XMLHTTP");
}catch(e3){
xmlhttpobj = false;
}
}
}
return xmlhttpobj;
}

function getsubcategory(bigclassid){
if(bigclassid==0){
document.getElementById("subclass").innerHTML="选择二级分类";
return;
};
var xmlhttpobj = createxmlhttp();
if(xmlhttpobj){//如果创建对象xmlhttpobj成功
xmlhttpobj.onreadystatechange=handle;
xmlhttpobj.open('get',"getsubcategory.asp?bigclassid="+bigclassid+"&number="+Math.random(),true);//get方法 加个随机数。

xmlhttpobj.send(null);
}
}

function handle(){//客户端监控函数
//if(xmlhttpobj.readystate==4){//服务器处理请求完成
if(xmlhttpobj.status==200){
//alert('ok');
var html = xmlhttpobj.responseText;//获得返回值
document.getElementById("subclass").innerHTML=html;
}else{
document.getElementById("subclass").innerHTML="对不起，您请求的页面有问题...";
}
//}
//else{
//document.getElementById("subclass").innerHTML=xmlhttpobj.readystate;//服务器处理中
//}
//}

}

<%
set cmd = conn.execute("select bigclassid,bigclassname from bigclass")
tempid=cmd("bigclassid")
%>

<%
if not cmd.eof then
do while not cmd.eof
bigclassid= cmd("bigclassid")
bigclassname = cmd("bigclassname")
%>

<%=bigclassname%>
<%
cmd.movenext
loop
end if
cmd.close
set cmd = nothing
%>