asp中文数字验证码

<form method="post" name=myform>
姓　名：<input type="text" name="name" value=""><br>
学　号：<input type="text" name="num" value=""><br>
。。。：<input type="text" name="aaa" value=""><br>
。。。：<input type="text" name="bbb" value=""><br>
验证码：<img src="vcode/c.asp" onclick="this.src=this.src" title="点击图片可以更改验证码" height="13" width="52">
<input type="text" size="5" name="c" autocomplete="off" style="ime-mode:disabled;" value="">
<input type="submit" value="提交">
</form>

<%
c = request.form("c")
'如果可以输入小写的数字，请把下面三行注释掉
for ii = 0 to 9
c = replace(c,cstr(ii),"")
next
c = replace(c,"零","0")
c = replace(c,"一","1")
c = replace(c,"二","2")
c = replace(c,"三","3")
c = replace(c,"四","4")
c = replace(c,"五","5")
c = replace(c,"六","6")
c = replace(c,"七","7")
c = replace(c,"八","8")
c = replace(c,"九","9")
if cstr(c) <> cstr(session("validatecode")) then
response.write ("验证码不正确")
response.end
end if
%>