asp投票模块，按钮是图片的，提交不成功
不知道哪里有问题，请高手指点一下
<!--#include file="inc/conn.asp"-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns=" http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>
<body>
<table width="244" height="194" border="0" cellpadding="0" cellspacing="0" >
<tr>
<td width="245" height="22" align="left" background="images/mm_ai.jpg"> 在线调查</td>
</tr>
<tr>
<td height="175" align="center" valign="top" background="images/mm_ao.jpg">
<form id="form1" name="form1" method="post" action="">
<table width="82%" border="0" cellspacing="0" cellpadding="0" >
<tr>
<td height="21" align="left">您是通过何种方式了解本站的？</td>
</tr>
<%
sql_tou="select * from tou"
set rs_tou=conn.execute(sql_tou)
%>
<%do while rs_tou.eof=false%>
<tr>
<td height="19" align="left"><input name="id" type="radio" value="<%=rs_tou("id")%>" />
<%=rs_tou("touitem")%></td>
</tr>
<%rs_tou.movenext
loop%>
<tr>
<td height="24" align="left" valign="bottom">
<input name="submit" type="image" id="submit" value="投票" src="images/toupiao.jpg" />
<img src="images/chakan.jpg" width="47" height="15" /></td>
</tr>
</table>
</form>
</td>
</tr>
</table>
</body>
</html>
<%
if request.Form("submit")="投票" then
id=request.Form("id")
sql2="update tou set toucount=toucount+1 where id="&id
conn.execute(sql2)
%>
<script language="javascript">
alert('恭喜您，投票成功！');
</script>
<%
end if
%>