接受语句完全正确就是第三个和第四个的sno接受后经判断为空，但是我不是提交的空值
<html>
<head>
<title>网上查分</title>
<SCRIPT LANGUAGE="JavaScript">
<!--
function fsubmit()
{
if(searchForm.rcond[0].checked)
{
searchForm.action="alterData.jsp?cond=all"
}
else if(searchForm.rcond[1].checked)
{
searchForm.action="alterData.jsp?cond=alter"
}
else if(searchForm.rcond[2].checked)
{
searchForm.action="alterData.jsp?cond=add"
}
else if(searchForm.rcond[3].checked)
{
searchForm.action="alterData.jsp?cond=delete"
}
}
function hideall()
{
if(searchForm.rcond[0].checked)
{
pre.style.display = "none";
pre1.style.display = "none";
key.style.display = "none";
}
}
function showpre()
{
if(searchForm.rcond[1].checked)
{
pre.style.display = "";
pre1.style.display = "none";
key.style.display = "none";
}
else
{
pre.style.display = "none";
}
}
function showpre1()
{
if(searchForm.rcond[2].checked)
{
pre1.style.display = "";
pre.style.display = "none";
key.style.display = "none";
}
else
{
pre1.style.display = "none";
}
}
function showkey()
{
if(searchForm.rcond[3].checked)
{
key.style.display = "";
pre.style.display = "none";
pre1.style.display = "none";
}
else
{
key.style.display = "none";
}
}
//-->
</SCRIPT>
</head>
<body>
<form name="searchForm" action="" method="post" onClick="fsubmit()">
<input type="radio" name="rcond" onclick="hideall()">查看所有记录<p>
<input type="radio" name="rcond" onclick="showpre()">修改信息<p>
<table id=pre >
<tr>
<td>学号:</td>
<td><input type="text" name="sno"></td>
</tr>
</table><p>
<input type="radio" name="rcond" onclick="showpre1()">添加信息<p>
<table id=pre1 >
<tr>
<td>学号:</td>
<td><input type="text" name="sno"></td>
</tr>
</table><p>
<input type="radio" name="rcond" onclick="showkey()">删除信息<p>
<table id=key >
<tr>
<td>学号:</td>
<td><input type="text" name="sno"></td>
</tr>
</table><p>
<input type="reset" value="重新输入">
<input type="submit" value="提交">
</form>
</body>
</html>