基于asp+ajax和数据库驱动的二级联动菜单

　　index.asp 页面代码
复制代码 代码如下:
<!--#include file=conn.asp -->
<%
set cmd = conn.execute(select bigclassid,bigclassname from bigclass)
tempid=cmd(bigclassid)
%>
<select name=menu onChange=getsubcategory(this.value);>

<%
if not cmd.eof then
do while not cmd.eof
bigclassid= cmd(bigclassid)
bigclassname = cmd(bigclassname)
%>
<option value=<%=bigclassid%>><%=bigclassname%></option>
<%
cmd.movenext
loop
end if
cmd.close
set cmd = nothing
%>
</select>
<div id=subclass>
<select name=submenu>

<%
set cxd = conn.execute(select * from smallclass where bigclassid= & tempid)
if not cxd.eof then
do while not cxd.eof
smallclassid= cxd(smallclassid)
smallclassname = cxd(smallclassname)%>
<option value=<%=smallclassid%>><%=smallclassname%></option>
<%
cxd.movenext
loop
cxd.close
set cxd = nothing
else
html = <select name=smallclassid><option value=0 selected>暂无小类</option></select>
response.write html
end if
%>
</select>
</div>

ajax.js 代码
复制代码 代码如下:
// 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){
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
//}
//}

}

getsubcategory.asp 代码
复制代码 代码如下:
<%@language=vbscript codepage=936%>
<!--#include file=conn.asp-->
<%
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 = <select name=select2>&vbnewline
do while not p.eof
html = html&<option value=&p(smallclassid)&>&p(smallclassname)&</option>&vbnewline
p.movenext
loop
html = html&</select>
else
html = <select name=smallclassid><option value=0 selected>暂无小类</option></select>
end if
p.close
set p = nothing
conn.close
set conn = nothing
response.write html
html =
end if
%>