关于用户注册时显示高级选项的问题
我正在做一个用户注册页面，可是显示不了高级设置选项，请问这段代码哪里需要改？谢谢各位！
程序代码：<html xmlns="http://www. >
<head runat="server">
<title>用户注册</title>
<style>
#f{border-collapse:collapse;}
</style>
<script type="text/javascript">
function showadv()
{
if(document.register.advshow.checked == true)
{
$("adv").style.display = "";
}
else
{
$("adv").style.display = "none";
}
}
</script>
</head>
<body>
<form id="form1" name="register" runat="server">
<table id="f" width="100%" border="1" cellpadding="10" cellspacing="0" rules="rows">
<thead>
<tr>
<th width="24%"><div align="left">基本信息 ( * 为必填项)</div></th>
<td width="76%"> </td>
</tr>
</thead>
<tr>
<th><label for="username"><div align="left">用户名*</div></label></th>
<td><input name="username" id="username" type="text" /></td>
</tr>
<tr>
<th><label for="password"><div align="left">密码*</div></label></th>
<td><input name="password" type="password" id="password" /></td>
</tr>
<tr>
<th><label for="checkpassword"><div align="left">确认密码*</div></label></th>
<td><input name="checkpassword" type="password" id="checkpassword"/></td>
</tr>
<tr>
<th><label for="validatecode"><div align="left">验证码*</div></label></th>
<td><input name="" type="text" /></td>
</tr>
<tr>
<th><label for="advshow"><div align="left">高级选项</div></label></th>
<td><label><input id="advshow" name="advshow" type="checkbox" onclick="showadv()"/>显示高级用户选项</label></td>
</tr>
</table>
<table summary="注册 高级选项" cellspacing="0" cellpadding="0" id="adv" style="display: none;">
<tr>
<td>高级用户选项</td>
</tr>
</table>
</form>
</body>
